1. Chandrasekhar, S.: 1945,Astrophys. J. 102, 223.
2. Czyzak, S. J.: 1968, in B. M. Middlehurst and L. H. Aller (eds),Nebulae and Interstellar Matter, Chicago University Press, Chicago, p. 403.
3. Froese-Fisher, C.: 1967,Con. J. Phys. 457.
4. Froese-Fisher, C.: 1969,Comp. Phys. Comm. 1, 151.
5. MCHF 77, Tech. Report No. 225;C. Froese-Fisher,1977