1. J. M. Powers, K. C. Ludema and R. G. Craig, Wear of fluorapatite single crystals. IV. Influence of sliding direction on frictional behavior and surface failure, submitted for publication to J. Dent. Res..
2. J. M. Powers, K. C. Ludema and R. G. Craig, Wear of fluorapatite single crystals. V. Influence of environment on frictional behavior and surface failure, submitted for publication to J. Dent. Res..
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