1. a Esso Research and Engineering Company and Humble Oil Refining Company , Linden, New Jersey
2. b Medical Research Division, Esso Research and Engineering Company , P. O. Box 45, Linden, New Jersey
3. c Medical Division, Humble Oil Refining Company , Baton Rouge, Louisiana
4. d Medical Division, Humble Oil and Refining Company , P. O. Box 222, Linden, New Jersey