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 Collection metrics at Scopus Article at Scopus Collection metrics at WOS Article at WOS