1. Adams, F.C., Emerson, J., and Fuller, G. 1990, Astrophys. J., 357, 606.
2. Adams, F.C., Lada, C.J., and Shu F.H. 1987, Astrophys. J. 312, 788.
3. Adams, F.C., Ruden, S.P., and Shu, F.H. 1989, Astrophys. J. 347, 959.
4. Agrawal, P.C., Rao, A.R., and Riegler, G.R. 1986, Mon. Not. Roy. Astr. Soc. 219, 777.
5. André, P. 1987, in Protostars and Molecular Clouds, eds. T. Montmerle and C Bertout (C.E.A.: Gif-sur-Yvette), p. 143.