1. ENVIRON Corporation 1000 Potomac Street, N. W. Washington, DC 20007
2. Biosafety Research Center, Foods, Drugs and Pesticides (An-Pyo Center), 582-2, Arahama, Shioshinden, Fukude-cho, Iwata-gun, Skizuoka-ken, Japan.
3. Department of Mutagenesis, Huntingdon Research Centre Ltd., Huntingdon, Cambridgeshire, England.