| title | ISBN-13 (ISBN-10) | year of publication |
|---|---|---|
| A bibliography of occupational health and safety in the Philippines | 978-971-91131-4-0 (971-91131-4-6) | 1990 |
| Philippine directory of occupational health and safety | 978-971-91131-2-6 (971-91131-2-X) | 1989 |
H.J. · H.J. Wolff · H. Juergen · H.W. · H. Wolff · Hans J. Wolff · Hans Jürgen · Hans Wolff · J. W. · J Wolff · Jürgen Wolff