D. S. Yan, Microstructure and Properties of Post Sintered RBSN Containing YAG as Grain Boundary Phase, Presented at International Symposium on Ceramic Components for Engine, Hakone, Japan, Oct. 1983, 17-21, (appeared in the Proceedings), Eds. S. Somiya,et al. KTK Scien. Publishers, 1984,368.