1. a Celanse Research company , Summit
2. c Petrochemical and Polymer Laboratory , I.C.I. Ltd. , Runcorn, Cheshire, England
3. d Esso Chemical Co , New York, N. Y.
4. e International Business Machines Corp , Boulder, Colo.
5. b Camile Dray-fus Laboratory , Research Triangle Institute , Durham, N.C
6. f National Bureau of Standards , Gaithersburg, Md.
7. g Research Services, Inc. , Minnetonka, Minn.