1. Empirical calculation of conformation;GILL;Prog. med. Chem.,1965
2. EHT conformation compared with X-ray structure;KIER;Molec. Pharmac.,1967
3. EHT calculation; comparison with nicotine; charge densities;KIER;Molec. Pharmac.,1968
4. Empirical calculation;LIQUORI;J. molec. Biol.,1968
5. EHT calculation;FARKAS;Nature, Lond.,1969