1. Bastien, P.: 1989, in G.V. Coyne et al., ed(s)., Polarized Radiation of Circumstellar Origin, (Vatican City: Vatican Press), 541
2. Beckwith, S.V.W., Sargent, A.I.: 1992, in H. Levy, J.I. Lunine, ed(s)., Protostars and Planets III, (Tucson: Univ. of Arizona Press), in press
3. Bieging, J., Cohen, M., Schwartz, P.R.: 1984, Astrophys. J. 282, 699
4. Blandford, R.D., Payne, D.G.: 1982, M.N.R.A.S. 199, 883
5. Edwards, S., Cabrit, S., Strom, S.E., Heyer, I., Strom, K.M., Anderson, E.: 1987, Astrophys. J. 321, 473