The following publications are possibly variants of this publication:
- Cross-border e-Government Services in Europe: Expected Benefits, Barriers and Drivers of the Once-Only PrincipleTarmo Kalvet, Maarja Toots, Anne Fleur van Veenstra, Robert Krimmer. icegov 2018: 69-72 [doi]
- Drivers for and Barriers to the Cross-border Implementation of the Once-Only PrincipleNele Leosk, Irma Põder, Carsten Schmidt, Tarmo Kalvet, Robert Krimmer. In Robert Krimmer, Andriana Prentza, Szymon Mamrot, editors, The Once-Only Principle - The TOOP Project. Volume 12621 of Lecture Notes in Computer Science, pages 38-60, Springer, 2021. [doi]
- The Once-Only Principle: A Matter of TrustRobert Krimmer, Andriana Prentza, Szymon Mamrot, Carsten Schmidt. In Robert Krimmer, Andriana Prentza, Szymon Mamrot, editors, The Once-Only Principle - The TOOP Project. Volume 12621 of Lecture Notes in Computer Science, pages 1-8, Springer, 2021. [doi]
- The Future of the Once-Only Principle in EuropeRobert Krimmer, Andriana Prentza, Szymon Mamrot, Carsten Schmidt, Aleksandrs Cepilovs. In Robert Krimmer, Andriana Prentza, Szymon Mamrot, editors, The Once-Only Principle - The TOOP Project. Volume 12621 of Lecture Notes in Computer Science, pages 225-236, Springer, 2021. [doi]
- Contributing to a digital single market for Europe: barriers and drivers of an EU-wide once-only principleTarmo Kalvet, Maarja Toots, Robert Krimmer. DG.O 2018: [doi]
- Exploring and Demonstrating the Once-Only Principle: A European PerspectiveRobert Krimmer, Tarmo Kalvet, Maarja Toots, Aleksandrs Cepilovs, Efthimios Tambouris. DG.O 2017: 546-551 [doi]
- Once-Only Principle Good Practices in EuropeMaria A. Wimmer. In Robert Krimmer, Andriana Prentza, Szymon Mamrot, editors, The Once-Only Principle - The TOOP Project. Volume 12621 of Lecture Notes in Computer Science, pages 61-82, Springer, 2021. [doi]