1. C. M. McNie, D. C. Barton, E. Ingham, J. L. Tipper, J. Fisher, and M. H. Stone: Journal of Materials Science: Materials in Medecine vol. 11: 3 (2000), p.163.
2. J. Dumbleton: Tribology of natural and artificial joints (Elsevier Scientific Publishing Company, 1981).
3. H. Dong, W. Shi and T. Bell: Wear, vol. 225-229 I(1999), p.146.
4. A. Unsworth, D. Dowson, V. Wright, D. Koshal: Journal of Lubrication Technology (1975), p.377.
5. Kenneth R. St. John and Audrey K. Tsao, in: Encyclopedic Handbook of Biomaterials and Bioengineering, Part A, Vol. 2, eds. D. L. Wise et al. (Marcel Dekker Inc, 1995).