Conformational analysis of bicyclic systems including the NCO unit by molecular mechanics. Part III. Perhydro-oxazolo [3,4-a] pyridine, perhydro- oxazolo [3,4-c] [1,3]oxazines and perhydro [1,3] oxazino [3,4-c] [1,3]oxazines

1. Fernández, B.
2. Carballeira, L.
3. A. Ríos, M.