Digital Antiquity staff and Board of Directors members were out in force at the 84th Annual Meeting of the SAA in Albuquerque, New Mexico.

With the highest attendance the SAA has seen – over 5,300 attendees! – the 4-day conference was filled with various meetings, sessions, and discussions with people at the exhibitor booth.

Rachel Fernandez with the Electric Symposium Group
Rachel Fernandez and Leigh Anne Ellison at the SAA tDAR Booth

Between the Digital Antiquity staff alone, we participated in over four sessions, sat on two committee meetings, lead a hands-on Digital Curation workshop, and spent countless hours at the exhibitor hall discussing the benefits and uses of tDAR.

Dr. Frank McManamon and Rachel Fernandez at the SAA tDAR booth
The tDAR Booth was visited by Meagan Dennison, Winner of the 2019 SAA Student Paper Award! As part of her prize, Digital Antiquity provided Meagan with 50 Files (up to 525 MB!) of repository space in tDAR to preserve and share her current and future research.

A meeting highlight of particular note was the Symposium 188, “Attention to Detail: A Pragmatic Career of Research, Mentoring, and Service, Papers in Honor of Keith Kintigh” in which our own Dr. Kintigh was recognized for his considerable contributions to the field of archaeology and advocacy for digital preservation. Among the speakers lauding Dr. Kintigh’s accomplishments were tDAR’s Founding Director Dr. Frank McManamon and Digital Antiquity Board Member, Jeffrey Altschul, further marking the session as a truly special event.

Dr. Keith Kintigh was recognized by his peers, colleagues, and mentees at the SAA Meeting
Dr. Frank McManamon speaking at Dr. Keith Kintigh’s SAA Symposium
Dr. Keith Kintigh Speaking at his SAA Symposium

Utilizing your SAA-Digital Antiquity Good Digital Curation Agreement Benefits

In order to preserve and readily share the incredible work of SAA Meeting presenters, the Center for Digital Antiquity has continued its Good Digital Curation Agreement partnership with the SAA, now into its fifth year. Through this partnership, all session abstracts from past conferences (2015-present) can be found on the tDAR website.  Further, if you are the author of an abstract(s), you can utilize your SAA Member Benefits to upload your presentation, paper, poster, or other supplementary data into tDAR for free (up to 30MB).

In addition to presenter benefits, the SAA also supports up to 10 free uploads (totaling 100MB) into tDAR for retired members, student members, members from countries with discounted membership rates, and members from Tribal Historic Preservation Offices.

Preserving and making your archaeological data accessible has never been easier! We hope you will take advantage of this opportunity to enrich future research by uploading your archaeological information into tDAR. You can find your abstract and learn more about your SAA benefits here:

SAA Member Benefits page in tDAR

Recently, ASU archaeology Professor Keith Kintigh and Founding Director Frank McManamon were interviewed by Alexandra Witze, a writer for the Archaeological Conservancy’s “American Archaeology” Magazine.  The Archaeological Conservancy is a non-profit organization whose mission is to identify, acquire and preserve significant archaeological sites in the U.S. That mission dovetails nicely with our mission at Digital Antiquity: to acquire, preserve and make accessible the digital data associated with archaeological research.  In the article, Frank and Keith recount the urgent need to upload digital archaeological data to repositories like tDAR.

Most archaeologists aren’t curating their digital data at public repositories like tDAR. Kintigh stressed that proper curation is more important than ever because now much of this information is, so to speak, “born digital” and exists in no other form. Without it, future generations of scientists won’t be able to reanalyze and synthesize the information and make fresh discoveries of their own. “It’s a tragedy that we’re not adequately capitalizing on the potential uses of the data,” he said.

This follows on the heels of a forthright article by Keith last fall in “The Conversation,” where he argued strongly that “agencies must ensure that the full digital record of their archaeological investigations is deposited in a recognized digital repository.” tDAR has worked effectively with a number of agencies (Dept. of Defense, Bureau of Land Management, and the Bureau of Reclamation, among others) to make archaeological information discoverable, accessible and preserved permanently for future use.

Check out the “Disappearing Data” article on the Archaeological Conservancy website.

Digital Antiquity is pleased to announce some recent staffing changes.  In November 2018, our long serving Director of Technology, Adam Brin, accepted a new position at the Getty Museum in Los Angeles, CA.  Digital Antiquity is a small team of highly skilled people who, together, have built an amazing online repository backed by sophisticated data management services.  None of that would have been possible without Adam’s work over the years. We will miss him, and wish him great success in his exciting new career with the Getty.

When one door closes, another opens, as the saying goes.  So it is with tDAR, as we now welcome (back) Digital Software Engineer Jim deVos.  Jim worked at tDAR in the early days, and now has rejoined our team to help us move forward into our second decade. It’s an exciting time with several new projects in the offing. Jim’s background – from Qwest, to Honeywell, to the ASU Library and back to Digital Antiquity – brings a wonderful mixture of skills and experience that will enable us to continue to deliver the highest quality technical services.

Also joining the tDAR team is Administrative Specialist Charlene Collazzi.  Charlene has a strong background in archaeology, participating in fieldwork projects in Chile, Panama, and Egypt on the way to earning her Bachelor’s degree in Anthropology at UCLA. Before joining Digital Antiquity in December, she held various Administrative positions at the UCLA Medical Center and most recently at the Boulder County Land Use Department in Colorado. Charlene is in charge of our business processes, manages the office, and heads up tDAR communications duties including website and social media posts.

The 84th Annual Society for American Archaeology meeting is just around the corner, and Digital Antiquity staff look forward to participating in a variety of symposiums, forums, and other events throughout the week of April 10-14, 2019 in Albuquerque, New Mexico! Digital Antiquity highlights will include a symposium honoring the illustrious career of Keith Kintigh (4/12), a workshop geared towards helping SAA members utilize tDAR’s digital data curation services (4/13), and many other exciting happenings listed below.  

Digital Antiquity staff will also be on hand at Exhibit Hall booth #505 throughout the week, so be sure to stop by with any tDAR or digital curation related questions, learn more about the SAA/Center for Digital Antiquity Good Digital Curation Agreement, enroll in our raffles to win some great prizes, or just stop by to say hi!

Follow us on Twitter @DigArcRec  and Instagram at digitalantiquity for up-to-the-minute tDAR news throughout the conference!

  • Thursday, April 11, 2019
    • Digital Antiquity Booth
      • Room: Exhibit Hall in Hall 4 (ACC)
      • Booth #: 505
      • Time: 9:00 AM – 5:00 PM
    • Symposium: [34] Zooarchaeology and Technology: Case Studies and Applications
      • Room: 140 Aztec
      • Time: 8:00 AM – 12:00 PM
      • Highlight: 8:15 AM “Mapping Faunal Data to tDAR Ontologies to Address Data Comparability and Archaic Period Use of Animals in the Interior Eastern United States” —Bonnie Styles, Mona Colburn and Sarah Neusius
    • Electronic Symposium: [134] Towards a Standardization of Photogrammetric Methods in Archaeology: A Conversation About ‘Best Practices’ in an Emerging Methodology
      • Room: 10 Anasazi
      • Time: 6:00 PM – 8:00 PM
      • Highlight: Digital Curation of Photogrammetric Data —Rachel Fernandez

  • Friday, April 12, 2019
    • Digital Antiquity Booth
      • Room: Exhibit Hall in Hall 4 (ACC)
      • Booth #: 505
      • Time: 9:00 AM – 5:00 PM
    • Symposium: [188] Attention to Detail: A Pragmatic Career of Research, Mentoring, and Service, Papers In Honor of Keith Kintigh
      • Room: 275 Ballroom B
      • Time: 8:00 AM – 11:00 AM
      • Highlight: 10:15 AM “Promoting an Archaeological Perspective in Repatriation, Consultation, National Monuments, and Data Science —Francis McManamon
    • Forum: [225] From “Saving the Past for the Future” to “Saving the Future with the Past”: Building Arguments for Contemporary Relevance
      • Room: 220 Ruidoso
      • Time: 1:00 PM – 3:00 PM
      • Highlight: Keith Kintigh and Jeffrey Altschul, Moderators
    • Symposium: [237] Beyond Collections: Federal Archaeology and “New Discoveries” Under NAGPRA
      • Room: 130 Cimarron
      • Time: 1:00 PM – 3:30 PM
      • Highlight: 3:00 PM Discussant —Francis McManamon
    • Symposium: [256] I Love Sherds and Parasites: A Festschrift in Honor of Pat Urban and Ed Schortman
      • Room: 280 Ballroom A
      • Time: 1:00 PM – 5:00 PM
      • Highlight: 2:15 PM “Lessons That Can’t Be Taught: Applying Anthropology in Honduras and Beyond” —Claire Novotny, Anna Novotny and Leigh Anne Ellison

  • Saturday, April 13, 2019
    • Digital Antiquity Booth
      • Room: Exhibit Hall in Hall 4 (ACC)
      • Booth #: 505
      • Time: 11:00 AM – 5:00 PM
    • Workshop: Using tDAR: A Workshop for SAA Members Benefiting from the SAA–Center for Digital Antiquity Good Digital Curation Agreement
      • Room: Enchantment C-D, Foyer
      • Time: 9:00 AM – 10:30 AM
      • Workshop Leaders: Leigh Anne Ellison and Rachel Fernandez

We hope to see you all there!

Happy Centennial, Grand Canyon National Park from Digital Antiquity and tDAR

The Grand Canyon is an astonishing natural resource that has enchanted humankind for thousands of years. As evidence, this national treasure is filled with ancient and historical archaeological sites, cultural landscapes, and historic structures. 

In honor of Grand Canyon National Park’s Centennial, we invite you to dig into the Grand Canyon’s near and distant past by accessing maps, photos, research, and other resources available in tDAR!

As always, tDAR’s wealth of archaeological resources are free to access and share! Register for free to learn more about the incredible cultural landscape of the Grand Canyon!

Parashant tDAR webpage

The Center for Digital Antiquity is seeking a visionary Lead Software Engineer to help develop and expand the software infrastructure and services of tDAR (the Digital Archaeological Record), a state-of-the-art international digital repository for archaeological and cultural heritage data. This is a unique opportunity to lead the technical development of innovative systems and tools for digital data management, preservation, and sustainable access to the digital repository.

This position works with the development team to design, implement, document, and support tDAR. The ideal candidate will possess knowledge of general programming paradigms and languages, full-stack development, open source data repository platforms, and experience with full-text search platforms including but not limited to: Java, Python, Ruby, PostgreSQL, Apache Solr, Fedora, DSpace, HubZero, and Dataverse. This position reports to the Center for Digital Antiquity’s Executive Director and Board of Directors.

To learn more and to apply, visit the Arizona State University employment website. Applications will be accepted through January 21, 2019.

Workshop Dates: November 19- 23, 2018

Location: University of Ghana, Department of Archaeology and Heritage Studies

Participants: University of Ghana, Dept. of Archaeology and Heritage Studies Faculty and Students, Ghana Museum and Monuments Board Staff, University of Ghana, Institute of African Studies

Workshop Instructors: Ann Stahl, University of Victoria, Dept. of Anthropology, Lisa Goddard, University of Victoria Libraries, Rachel Fernandez, Center for Digital Antiquity

Recently, our Senior Digital Curator, Rachel Fernandez, along with Ann Stahl and Lisa Goddard from the University of Victoria, had the opportunity to lead a week-long workshop at the University of Ghana in Accra. This workshop is part of a larger Social Sciences and Humanities Research Council (SSHRC) of Canada Partnership Development grant titled, “Improving African Future Using Lessons from the Past” (IAfF). Partners on this grant include the University of Victoria, the University of Ghana, Ghana Museums and Monuments Board, Center for Digital Antiquity, and the Banda Traditional Council. The grant focuses on creating digital heritage collections that are not only relevant to scholars but to local communities and the broader public, with the idea of fostering digital heritage “communities of practice.”

At the kickoff workshop for the grant, a great group of 30 students, faculty, and staff participated in a series of lectures and hands-on activities throughout the week that touched upon topics such as best practices for digital data management and converting slides into digitized files.

By the end of the intensive week, the group had the chance to digitize documents, sort and digitize color slides, take photos and videos with audio, organize documents and add important metadata, and lastly, make draft digital data management plans to help them organize their own projects.  

Rachel was able to not only talk about the curation and planning activities that the Center for Digital Antiquity is able to provide, but also learned  about the challenges and innovative projects that are happening in Ghana. This partnership and workshop is a great example of how the archaeological community can come together with broader local and national communities to provide greater accessibility and increase preservation of valuable cultural heritage resources. We look forward to continuing working on this project and assisting in the workshops to come.

This past fall, Digital Antiquity had the opportunity to work with a new student intern, Lauren Tennison. As part of her internship, Lauren helped with adding content to tDAR for the Digital Archive of Huhugam project as well as learning skills in curation and redaction of archaeological reports. We are so happy to have had Lauren on board!

Fort Vermilion, Alberta, 2018

Name: Lauren Tennison

Position/Title: Digital Curation Intern

Degree: Currently pursuing a Bachelor’s degree in anthropology with a concentration in archaeology at Arizona State University.

Previous Work Experience/Research Focus: I excavated, surveyed, and did research at a Colonial era fur trading site in Alberta, Canada.  I also excavated and surveyed at a few Hohokam sites in Phoenix, Arizona.

Favorite Places to Travel to: My grandmothers in Cottonwood, Arizona and anywhere new.

Fun fact: I graduated with an Associate of Science degree from Weatherford College, Weatherford, Texas.  Then, I transferred to Arizona State to get my Bachelors of Business in Global Logistics Management.  After a few semesters of that I realized where my real passions were and changed majors.

Favorite Collection: I’ve really enjoyed working on DAHA, the Digital Archive of Hohokam Archaeology. I love seeing how widespread their empire was. 

The Center for Digital Antiquity is currently seeking an Administrative Specialist and we invite all qualified applicants to apply. This position plays a vital role within our organization. We are seeking applicants who are motivated, self-directed, and shows professionalism in working directly with the Executive and Associate Directors on administrative matters related to general operations, financial resources management, client relations, and project coordination.

To learn more and to apply, visit the Arizona State University employment website. Application deadline is October 22, 2018 at 3:00pm (MST).

Wider use of tDAR (the Digital Archaeological Record) would be a valuable contribution to streamlining the Section 106 and other environmental review procedures at both the beginning of the process and at the end (McManamon et al. 2017). Let’s first consider how including a search of tDAR’s digital content at the beginning of Section 106 or NEPA reviews could help. Discussions and presentations at the September 2018 annual ACRA (American Cultural Resource Association) conference last month in Cincinnati emphasized the imperative of identifying the location of known historic properties early in the review. Agencies or developers who are considering undertakings need to have information about where known historic properties are located. One such source of this information is the SHPO (State Historic Preservation Office) statewide historic property inventory maintained by each state, which must be searched as part of the planning for any such undertaking.

SHPO historic property inventory records typically contain basic geographic and limited descriptive information, for example, name of the property, property type, ownership, category of significance, etc. However, in most cases, the SHPO inventory records are not substantially updated or expanded. These records do not provide the much more detailed descriptive, analytical, and evaluative information or links or easy access to existing data from more detailed studies of the historic properties.

Some SHPOs have accessible inventories of reports submitted as part of earlier Section 106 reviews. While some inventories may also include links between the reports of past investigations and the historic property inventory, many do not. In addition, most SHPOs limit access to and/or charge for use of their digital files, both the historic property inventory records and their reports of investigations libraries, so providing wider access is a challenge administratively and technically.

In her presentation at the ACRA conference, Marion Werkheiser made the point that easier access to and broader use of the “treasure trove” of additional information from past investigations would be beneficial for speeding up archaeological, environmental, and historic preservation reviews. The fuller contextual, descriptive, and interpretive information provided by these materials substantially enhance the typically sparse records contained in the SHPO inventories. The full extent of the data treasure trove is not known, but recent compilations (Altschul 2016:68-71; Departmental Consulting Archaeologist 2009: 41-44, 2010: 50-56) indicate that it encompasses millions of reports, images, data sets, and other kinds of files, some paper, but many already in digital formats. It is a terrible waste of (mostly) public funds and the results of much human endeavor not to make better use of this trove of existing data.

Content in tDAR includes these more detailed data, primarily in technical reports of investigations, but also in images, data sets, and other files deposited in tDAR. Much of this contextual and other substantive information derives from prior Section 106 or Section 110 or NEPA investigations. If a streamlined Section 106 process included a search of tDAR, the results would enable project proponents and their cultural resource management (CRM) consultants or staffs to obtain a fuller view of what work already had been done in potential impact areas and relative easy access to the results of these prior studies. In most cases, this detailed information is needed as part of the Section 106 review, which, in addition to simply identifying where historic properties are located, must assess their significance and value(s), determine if they will be impacted by the undertaking, and suggest how adverse impacts anticipated by the undertaking can be mitigated.

Digital searching of tDAR content is possible using geographic terms, key words, text strings, individual or groups of terms, and other means. In a streamlined review process, such searches would supplement what can be learned from basic SHPO historic property inventories. The tDAR metadata records, which are available for all files deposited in tDAR, are publicly accessible. Search of these digital records would not require any coding for special access. Access to the digital files themselves can be controlled with additional review of requests for access required (more on this process below).

A second way that using tDAR can improve and streamline review procedure is at the end of the investigation process. Data created by any Section 106 or environmental review-related investigation should be deposited in tDAR as part of the project itself, analogous to the mandatory deposit of physical collections and paper records in a qualified curatorial repository at the end of a project. As is clear from the detailed legal analysis by Cultural Heritage Partners (2012), the requirement for up-to-date digital data curation exists in 36 CFR 79, the National Archives and Records Administration regulations, and the statutes from which these regulation derive.

Depositing data in tDAR as part of a project is easily accomplished administratively by including in all investigation scopes of work the requirement that the CRM or environmental consulting firm carrying out the work upload to tDAR and complete the metadata records for the digital products (mainly documents, images, data sets) of their investigation. A number of examples are summarized below. By including this activity as part of the CRM contract, the new data becomes immediately available for use by and for new projects. With these data deposits, the information treasure trove grows with the completion of each current CRM investigation.

Concern is often raised about access to certain kinds of archaeological data, for example, very specific information about the location of in situ resources that may be in some documents, forms, data sets, etc. Data deposited in tDAR can be marked as “confidential” at the time they are uploaded. This designation requires that others who wish to see or download the confidential files must contact the individual or organization that authorized the deposit of the files and be given access to the files by the depositor. This provides for an extra level of protection for confidential data deposited in tDAR. It also is possible for those who deposit data in tDAR to create, using readily available commercial software, “redacted” versions of documents or other files from which confidential data are removed. These redacted versions can be deposited and made available in tDAR to registered tDAR users who have agreed formally to give credit to the data creator(s) if the data are used for subsequent research and not to take any actions that would endanger the resources to which the data relate. Several agencies and firms that have created digital archives in tDAR to manage their digital archaeology and cultural heritage data. These tDAR users create redacted versions, as well as, deposit confidential full versions of their data. This approach enables them to control access to the confidential data, but also provides wider and easier public and professional access to data that is not confidential.

SHPOs, of course, will want and should have copies of reports and related material in their own offices where they can make use of them. A strategy for long-term digital data preservation envisions many copies of the data being preserved and available for reuse in multiple repositories. It is not a problem if data are cared for in more than a single repository. A growing number of examples exist of public agencies (national, state, local, and, soon we hope, tribal programs) depositing data in tDAR where they can use the data more effectively and efficiently and manage access. Below are several recent examples.

Phoenix Area Office (PXAO), Bureau of Reclamation:

This extensive archive, set up in 2011 is the first digital archive collection in tDAR. It is used actively by PXAO CRM staff to manage their data (Digital Antiquity 2013). Currently the archive includes 11 datasets, 371 documents, 5 GIS datasets, 56 images, and 103 projects. Growth continues both through the addition of legacy data and through the inclusion of data from recent or current projects. In terms of the resources in this tDAR collection being discoverable, accessible, and used, in 2017 and 2018, resources in the collection have been viewed over 57,180 times and files downloaded 5,534 times.


SWCA (a CRM firm based in Colorado):

The firm deposited data from a recent project, the Sigurd to Red Butte No. 2 transmission line in UT. This project archive includes 12 data sets and 10 documents (reports, artifact data sets and site inventory forms). The site inventory forms are marked in tDAR as confidential and have access controlled by SWCA and the BLM. The physical collections are curated at the Natural History Museum of Utah. The project digital data were deposited as the final part of a project overseen by BLM and funded by a private energy company. The files and metadata records were uploaded to tDAR by SWCA as a project deliverable. Throughout this project, 81 sites were investigated in some combination of Phase I testing, Phase II excavation, and/or Level II historical documentation. The CRM firm that undertook this project, SWCA, was requested to take on the project in May of 2015. The project data was deposited in tDAR in June, 2017. That is a quick “turn-around” time from project start to project data being made available. In this case it was possible by using tDAR as the data repository where other potential users can discover, access, and make use of the data.


Dovetail Research Group (a CRM firm based in North Carolina):

The firm deposited as part of their project completion the data from excavations of the Armstrong-Rogers Site (7NC-F-135) (Hatch et al. 2017). The excavation is part of a larger archaeological program for developments of the U.S. Route 301 Corridor, New Castle County, Delaware. This project archive consists of 3 datasets and 2 documents, Phase III investigations. The project is part of the Delaware Department of Transportation (DelDoT) Digital Archive in tDAR, which is described in the next bullet.


DelDoT Digital Archive, Delaware Dept. of Transportation:

So far data from five recent major archaeological projects done as part of the Route 301 project. At present, the archive includes 15 data sets, 6 reports, and 30 sets of images. These data are organized under five projects carried out by different CRM firms as part of the overall impact mitigation program for the highway project.


Far Western Anthropological Research Group, Inc. (a CRM firm based in California):

Far Western deposited data for two recent projects on behalf of their client, the Bureau of Reclamation Lower Colorado River office. Archaeological Inventory of 1,927 Acres Atop and Adjacent to Mormon Mesa, Clark County, Nevada (2018) and Class III Cultural Resources Inventory of 1,555 Acres East of the Virgin River, Clark County, Nevada (2018). For this project, the fieldwork was completed in January 2018 and the documents and data sets were uploaded and made available in July 2018.


Managing or curating data is an important, albeit, frequently overlooked part of any research project no matter what the subject area or reason behind the study. Good management of digital data requires that they be broadly and easily discovered, accessed, understandable for reuse, and preserved for future uses. The desire among data users for greater transparency and access is widespread among both the scientific and humanities disciplines and with policy makers. This is particularly true for data that have been produced at public expense, e.g., through funding agencies such as EPA, NSF, NEH, NIH, and USGS. The demand for greater access to sponsored project research data is focused on issues such as what data are saved by such publicly funded or required projects; where and how can such data be discovered and accessed; and, what metadata are curated with these data files that make them usable. The recent research about how data are managed by York, Gutmann, and Berman (2018) describes some of the challenges in this area. Depositing data in tDAR as part of the completion of investigations is one way to ensure that project results do not broaden an already existing data stewardship gap in archaeology, historic preservation, and heritage studies.

References Cited

Altschul, Jeffery H. (2016) The Role of Synthesis in American Archaeology and Cultural Resource Management as Seen through an Arizona Lens. Journal of Arizona Archaeology 4(1):68–81., accessed 4 October 2018.

Cultural Heritage Partners, PLLC (2012) Federal Laws and Regulations Requiring Curation of Digital Archaeological Documents and Data., accessed 4 October 2018.

Departmental Consulting Archeologist (2009) The Goals and Accomplishments of the Federal Archeology Program: The Secretary of the Interior’s Report to Congress on the Federal Archeology Program, 1998-2003. Archaeology Program, National Park Service, Department of the Interior, Washington, DC. doi:10.6067/XCV81N7ZR4, accessed November 30, 2016.

Departmental Consulting Archeologist (2010) The Secretary of the Interior’s Report to Congress on the Federal Archeology Program, 2004-2007. Archaeology Program, National Park Service, Department of the Interior, Washington, DC. doi:10.6067/XCV8Q81DZV, accessed November 30, 2016

Digital Antiquity (2013) Case Study: Using tDAR to Manage Legacy and New Archaeological Documents and Data, the Phoenix Area Office of the Bureau of Reclamation., accessed 4 October 2018 .

Hatch, Brad, Danae Peckler, Joseph Blondino, Kerry S. Gonzalez, Emily Calhoun, Kerri S. Barile (2017) Archaeological Data Recovery at the Armstrong-Rogers Site(7NC-F-135) New Castle County, Delaware. D. (tDAR id: 446689); doi:10.6067/XCV8ZC85SX., accessed 4 October 2018.

McManamon, Francis P., Keith W. Kintigh, Leigh Anne Ellison, and Adam Brin (2017) tDAR: A Cultural Heritage Archive for Twenty-First-Century Public Outreach, Research, and Resource Management. Advances in Archaeological Practice 5(3):238-249., accessed 4 October 2018.

York, Jeremy, Myron Gutmann, and Francine Berman (2018) What do we know about the stewardship gap? Data Science Journal 17:1-17., accessed 4 October 2018.