Generic federated OOP architecture (1st version) : The Once-Only Principle Project [Online resource]Tepandi, Jaak; Verhoosel, Jack P. C.; Zeginis, Dimitris; Täks, Ermo2017

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