Drivers for and barriers to the cross-border implementation of the once-only principleLeosk, Nele; Põder, Ille; Schmidt, Carsten; Kalvet, Tarmo; Krimmer, Robert JohannesThe once-only principle : The TOOP project2021 / p. 38–60 https://doi.org/10.1007/978-3-030-79851-2_3 Collection metrics at Scopus Article at Scopus Collection metrics at WOS Article at WOS

The once-only principle : a matter of trustKrimmer, Robert Johannes; Prentza, Andriana; Mamrot, Szymon; Schmidt, CarstenThe once-only principle : The TOOP project2021 / p. 1-8 https://doi.org/10.1007/978-3-030-79851-2_1 Article collection metrics at Scopus Article at Scopus Article collection metrics at WOS Article at WOS

PrefaceKrimmer, Robert; Prentza, Andriana; Mamrot, SzymonThe once-only principle : The TOOP project2021 / 1 p https://link.springer.com/book/10.1007/978-3-030-79851-2 Article collection metrics at Scopus Article at Scopus Article collection metrics at WOS

The future of the once-only principle in EuropeKrimmer, Robert Johannes; Prentza, Andriana; Mamrot, Szymon; Schmidt, Carsten; Cepilovs, AleksandrsThe once-only principle : The TOOP project2021 / p. 225–236 https://doi.org/10.1007/978-3-030-79851-2_12 Article collection metrics at Scopus Article at Scopus Article collection metrics at WOS Article at WOS

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

TOOP trust architectureBoldrin, Luca; Sellitto, Giovanni Paolo; Tepandi, JaakThe once-only principle : The TOOP project2021 / p. 126–140 https://doi.org/10.1007/978-3-030-79851-2_7 Article collection metrics at Scopus Article at Scopus Article collection metrics at WOS Article at WOS