1. National Institute of Public Health and Environmental Protection (RIVM), P.O. Box 1, 3720 BA Bilthoven, The Netherlands
2. Bayer AG, PF-Zentrum Mannheim, D-51368 Leverkusen, Germany
3. Bacterial Vaccine Department, Statens Seruminstitut, Artillerivej 5, DK-2300 Copenhagen S, Denmark
4. Institute of Virology and Immunoprophylaxis, P.O. Box 3147, Mittelhausern, Switzerland
5. European Pharmacopoeia Commission, B.P. 907, F-67029 Strasbourg Cedex 1, France
6. Paul Ehrlich Institut, P.O. Box 1740, D-63207 Langen, Germany
7. Afd. Biologische Standaardisatie, Ministerie van Hygiene en Epidemiologic, Juliette Wytmanstraat 14, B-1050 Brussels, Belgium
8. Coordination Vaccins, Agence du Medicament, Direction des Laboratoires et des Controles, Unité Pharmacologie-Toxicologie, 14 rue École de Pharmacie, 3400 Montpellier, France
9. WorldHealth Organisation—Biologicals, CH-1211 Geneva 27, Switzerland
10. Division of Virology, National Institute for Biological Standards and Control (NIBSC), Blanche Lane, South Mimms, Potters Bar, Hertfordshire EN6 3QG, UK
11. Rhone Merieux, Laboratoire IFFA, 254 rue Marcel Merieux, BP 7009, F-69007 Lyon, France
12. Galenica, Microbiology and Hygiene, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium
13. Behringwerke AG, Biological Research, P.O. Box 1140, D-35001 Marburg an der Lahn, Germany
14. lntervet Inc., 405 State Street, P.O. Box 318, Millsboro, DE 19966, USA
15. FRAME, Russell & Burch House, 96–98 North Sherwood Street, Nottingham NG1 4EE, UK
16. Istituto Superiore di Sanità, Laboratorio di Medecina Veterinaria, Viale Regina Elena 299, I-00161 Rome, Italy
17. Intervet International B.V., W. de Korvestraat 35, 5831 AN Boxmeer, The Netherlands.