1. Aikawa, T. and Whitney, C. A.: 1984,Astrophys. J. 282, 527.
2. Aikawa, T. and Whitney, C. A.: 1985,Astrophys. J. 296, 165.
3. Aikawa, T., Takeuti, M., and Uji-iye, K.: 1984, in M. Takeuti (ed.),Non-linear Phenomena in Stellar Outer-Layers, Tôhoku University, Sendai, Japan, p. 23.
4. Andreasen, G. K.: 1988a,Astron. Astrophys. 191, 71.
5. Andreasen, G. K.: 1988b,Astron. Astrophys. 196, 159.