1. MRC Common Cold Unit, Harvard Hospital, Coombe Road, Salisbury, Wilts SP2 8BW, U.K.
2. ICN European Medical Affairs Group, Eagle House, Peregrine Business Park, Gomm Road, High Wycombe, Bucks HP13 7DL, U.K.
3. ICN Nucleic Acid Research Institute, ICN Plaza, 3300 Hyland Avenue, Costa Mesa, CA 92626, U.S.A.