1. Camac, Camm, Feldman, Keck, and Petty, 26th Annual Meeting of the Institute of the Aeronautical Sciences, January 27, 1958.
2. J. A. Golden and A. L. Myerson, submitted to J. Opt. Soc. Am.
3. Private communication, R. G. Breene, Jr., these Laboratories, March, 1958.