1. Union Carbide Corporation, Carbon Products Division, 270 Park Ave., New York.
2. C. J. Sparks, unpublished paper presented at the 1967 ACA Meeting in Minneapolis.
3. Pyrolytic graphite as a second order neutron filter
4. Neutron powder diffractometry using a wavelength of 2.6 Å
5. W. C. Koehler, private communication.