1.
Berlin; Springer-Verlag; 1994.
in English
| WHO IRIS
| ID: who-41833
2.
Geneva; World Health Organization; 1994. (WHO/MNH/PSF/93.3 Rev.1. Unpublished).
in English
| WHO IRIS
| ID: who-62308
3.
Geneva; World Health Organization; 1994. (WHO/MNH/PSF/94.8. Unpublished).
in English
| WHO IRIS
| ID: who-61113
4.
Article
in English
| WHO IRIS
| ID: who-47443
5.
Article
in Spanish
| WHO IRIS
| ID: who-365207
6.
Article
in French
| WHO IRIS
| ID: who-365206