| title | ISBN-13 (ISBN-10) | year of publica- tion | other author(s) |
|---|---|---|---|
| Curricula and Lifelong Education: Studies for UNESCO | 978-92-3-101615-8 (92-3-101615-6) | 1981 | |
| Educational and Vocational Guidance Services for the 14-25 Age Group: Denmark, Federal Republic of Germany, and the Netherlands | 978-92-825-7856-8 (92-825-7856-9) | 1988 | F. Spoek · K. A. Heller |