1. Bash, F.N., and Peters, W.L.: 1976, Astrophys. J. 205, p. 786.
2. Blitz, L.: 1983, paper in these proceedings.
3. Burton, W.B., and Gordon, M.A.: 1978, Astron. Astrophys. 63, p. 7.
4. Burton, W.B., Gordon, M.A., Bania, T.M., and Lockman, F.J.: 1975, Astrophys. J. 202, p.30.
5. Caswell, J.L., and Haynes, R.F.: 1983, in preparation.