1. M. Pinneo and C. Bailey, US Patent 4939763, filed Oct. 3, 1988
2. L.S. Piano, K.V. Ravi, M. Peters, and M. Pinneo, European Patent Application EP 0365366 Al, priority Oct. 10, 1988
3. K.V. Ravi, L.S. Piano, M. Pinneo, M. Peters, and S. Yokota, in Science and Technology of NEW DIAMOND 1988, ed. S. Saito, O. Fukunaga, and M. Yoshikawa, KTK Scientific Publishers/Terra Publishing Company, Tokyo (1990), p. 29
4. T. Imai and N. Fujimori, European Patent Application 0476827 Al, priority Sept. 18, 1990
5. M.G. Peters, J.L. Knowles, M. Breen, and J. McCarthy, SPIE 1146, 217 (1989)