Communications from the David Dunlap Observatory

Reprints from various periodicals; distribution discontinued after no. 450.

Gorenstein, P., Harris, B., Gursky, H., Giacconi, R., Novic, R., and vanden Bout, P.
1971, Science, 172, 369. Goss, W. M., and Shaver, P. A. 1970, Australian J. Phys.
Suppl., No. 14, p. 1. Gott, J. R., Gunn, J. E., and Ostriker, J. P., 1970, Ap. J.