Genre
- Handbooks, manuals, etc 37 canlyniadau
- Case studies 14 canlyniadau
- Popular works 7 canlyniadau
- Longitudinal studies 3 canlyniadau
- Congresses 2 canlyniadau
- Cross-cultural studies 2 canlyniadau
- Biography 1 canlyniadau
- Classification 1 canlyniadau
- Miscellanea 1 canlyniadau
- Periodicals 1 canlyniadau
- Textbooks 1 canlyniadau