1. Batten, A.H. 1967 Publ. Dom. Astrophys. Obs. 13, 119.
2. Lucy, L.B. and Sweeney, M.A. 1971, Astr. J. 76, 544.
3. Moore, J.H. and Neubauer, F.J. 1948, Lick Obs. Bull. 20, 1.
4. Pedoussaut, A. and Carquillat, J.-M. 1973, Astron. Astrophys. Suppl. 10, 105.