1 C.H. Heiles, A.A. Goodman, C.F. McKee, and E.G. Zweibel, in (University of Arizona Press, 1993), p. 279.
1 C.F. McKee, E.G. Zweibel, A.A. Goodman, and C.H. Heiles, in (University of Arizona Press, 1993), p. 327.
1 B.-C.. Koo, W.T. Reach, C.H. Heiles, R.A. Fesen, and J.M. Shull, The Astrophysical Journal 364, (1990).