1. V. Weidemann: In The Second Conference on Faint Blue Stars, ed. by A.G. Davis Philip, D.S. Hayes and J.W. Liebert (Davis Press Inc., Schenectady, New York 1987) p.19
2. I. Iben: Quat. J. Roy. Astr. Soc. 26, 1 (1985)
3. D. Schönberner: In The Second Conference on Faint Blue Stars, see [1] p.201
4. Physical Processes in Red Giants, ed. by I. Iben and A. Renzini (Reidel, Dordrecht 1981)
5. Mass Loss in Red Giants, ed. by M. Morris and B. Zuckerman (Reidel, Dordrecht 1985)