1. London See also Katritzky in Topics in Heterocyclic Chemistry pp ed Wiley lnterscience : New York;Riddell;Quart Rev Chem Soc,1967
2. See CONFORMATIONAL ANALYSIS IN HETEROCYCLES See also Structure of Molecules and Interna / Rotation pp Aeademie Press : New York Bulf This suggestion has now been withdrawn : personal eommunieation b See also;Anteunis;Bull Soc Phys Tetrahedron Chem Soc Chem Commun,1966
3. Fora diseussion of a similar situation see;Mazaleyrat;Chem Commun,1969
4. See however a Allinger and;Siesie;Bull Org Chem,1967
5. See also;Eliel;Chem Soc,1969