1
Published 2007
Bundesministerium für Bildung und Forschung

2
Published 2014
Federal Office for Social Security

3
Published 2019
OECD Publishing

4
Published 2022
OECD Publishing

5
Published 2023
OECD Publishing

6
Published 2023
OECD Publishing

8
Published 2019
OECD Publishing

9
Published 2021
OECD Publishing

10
Published 2019
OECD Publishing

11
Published 2021
OECD Publishing

14
Published 2021
OECD Publishing

15
by Green, Andrew
Published 2019
OECD Publishing

18
Published 2019
OECD Publishing

19
Published 2020
OECD Publishing

20
Published 2020
OECD Publishing