• Evaluation of different designs to represent missing information in SQL databasesEessaar, Erki; Saal, ElariInnovations and advances in computer, information, systems sciences, and engineering2013 / p. 173-187 https://doi.org/10.1007/978-1-4614-3535-8_14 https://www.scopus.com/sourceid/19700186822 https://www.scopus.com/sourceid/19700186822
• On using a semiotic quality framework to evaluate the quality of conceptual database schemasEessaar, ErkiEmerging trends in computing, informatics, systems sciences, and engineering2013 / p. 103-115 https://doi.org/10.1007/978-1-4614-3558-7_9 https://www.scopus.com/sourceid/19700186822 https://www.scopus.com/record/display.uri?eid=2-s2.0-84865977954&origin=resultslist&sort=plf-f&src=s&sot=b&sdt=b&s=DOI%2810.1007%2F978-1-4614-3558-7_9%29&sessionSearchId=0906e4d58d0c902c55b98263cb85b6ec