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3. T. J. Gray, ?Processing of Crystalline Ceramics?, University Conference on Ceramic Science, 14th North Carolina State University, 1977, edited by Hayne Palmour, III, R. F. Davis and T. M. Hare (Plenum Press, New York, 1978) p. 479.
4. H. U. Anderson, R. Murphy, S. Semachaalbovorn, B. Rossing, A. Aldred, W. L. Procarione andR. J. Ackermann, Proceedings of the Conference on High Temperature Sciences Related to Open Cycle, Coal Fired MHD Systems (Argonne National Laboratory, Argonne, IL, 1977).
5. D. B. Meadowcroft, in Proceedings of the Conference on strontium Containing Compounds, Halifax, Canada, June 1973 (Atlantic Industrial Research Institute, Halifax, Nova Scotia, 1973) p. 119.