1. E. DÖRRE, H. BEUTLER and D. GEDLDIG, Arch. Orthop. Trauma. Surg. 83 (1975) 269.
2. G. HEIMKE, W. BEISLER, H. V. ANDRIAN-WERBURG, P. GRISS and B. KREMPIN, Ber. Dtsch. Keram. Ges. 50 (1973) 4.
3. G. HEIMKE, P. GRISS, H. V. ANDRIAN-WERBURG and B. KREMPIN, Arch. Orthop. Unfallchir. 78 (1974) 216.
4. J. HINTERBERG and M. UNGETHÜM, Arch. Orthop. Unfallchir. 116 (1978) 294.
5. M. SEMLITSCH, M. LEHMANNN, H. WEBER, E. DÖRRE and H. G. WILLERT, Med. Orthop. Tech. 5 (1976) 152.