1. Adams, T.F., Hummer, D.G., and Rybicki, G.B.: 1971, J. Quant. Spectrosc. Radiat. Transfer
11, 1365
2. Auer, L.H.: 1991, in Stellar Atmospheres: Beyond Classical Models. L. Crivellari, I. Hubeny, and D.G. Hummer (eds), p. 9
3. Auer, L.H. and Paletou, F.: 1994, Astron. Astrophys.
285, 675
4. Bommier, V.: 1997, Astron. Astrophys.
328, 726
5. Fabiani Bendicho P. and Trujillo Bueno, J.: 1999, in K.N. Nagendra, J.O. Stenflo (eds.), Solar Polarization, Proc. 2nd SPW, Kluwer, Dordrecht. (in this Volume)