1. T. P. Ruedi, Hefte Unfallheilkunde 123 (1975) 1.
2. P. G. Laing, in ?Tissue reaction to biomaterials? National Bureau of Standards, Special Publication, Washington DC 1977 p. 31.
3. B. A. Rahn, V. Geret, C. Capaul, M. Lardi and B. Solothurnmann, in ?Clinical Applications of Biomaterials?, edited by A. J. C. Lee, T. Albrektson, P. J. Branemark (Wiley, Chichester, 1982) p. 263.
4. T. N. Salthouse and B. E. Matlaga in ?Biomaterials in reconstructive surgery?, edited by L. B. Rubin (Mosby, St. Lous, 1983) p. 40.
5. T. Albrektsson, CRB Crit. Rev. Biocomp 1 (1985) 53.