• Generic federated OOP architecture (3rd version) : The Once-Only Principle Project [Online resource]Grandry, Eric; Fieten, Sander; Tepandi, Jaak; Täks, Ermo2018 http://toop.eu/sites/default/files/D23_Generic_Federated_OOP_Architecture_3rd_version.pdf
• The Once-Only Principle Project : Generic Federated OOP Architecture (2nd version) [Online resource]Grandry, Eric; Brandt, Paul; Dimitriou, Jerry; Fieten, Sander; Rotuna, Carmen; Tepandi, Jaak; Täks, Ermo; Verhoosel, Jack P. C.; Zeginis, Dimitris2018 http://www.toop.eu/sites/default/files/D22_Generic_Federated_OOP_Architecture_Final.pdf
• The technical challenges in OOP application across the European Union and the TOOP OOP architectureTepandi, Jaak; Rotuna, Carmen; Sellitto, Giovanni Paolo; Fieten, Sander; Prentza, AndrianaThe once-only principle : The TOOP project2021 / p. 141−163 https://doi.org/10.1007/978-3-030-79851-2_8 https://www.scopus.com/sourceid/25674 https://www.scopus.com/record/display.uri?eid=2-s2.0-85109977228&origin=inward&txGid=1443347572a4d79cb5ea10d86235e123 https://jcr.clarivate.com/jcr-jp/journal-profile?journal=LECT%20NOTES%20ARTIF%20INT&year=2005 https://www.webofscience.com/wos/woscc/full-record/WOS:000894547800010
• Towards a Cross-Border Reference Architecture for the Once-Only Principle in Europe : An Enterprise Modelling ApproachTepandi, Jaak; Grandry, Eric; Fieten, Sander; Draheim, Dirk; Piho, GunnarThe Practice of Enterprise Modeling : 12th IFIP Working Conference, PoEM 2019,Luxembourg, Luxembourg, November 27–29, 2019 : proceedings2019 / p. 103-117 https://doi.org/10.1007/978-3-030-35151-9_7 https://www.scopus.com/sourceid/17500155101 https://www.scopus.com/record/display.uri?eid=2-s2.0-85076686559&origin=inward&txGid=3aac6a2233d72e9b29b0fb4e59c7f34c https://www.webofscience.com/wos/woscc/full-record/WOS:000611409100007