1. Backman, S.: The proximal end of the femur. Acta radiol. (Stockh.) Suppl. 146 (1957)
2. Cotta, H., Schulitz, K.P.: Der totale Hüftgelenkersatz, Stuttgart: Thieme Verlag 1973
3. Engelhardt, A.: Experiences with the development and use of human implants made of Al2O3. Acta Orthopaedica Belgica 40, 699 (1974)
4. Engelhardt, A.: Experiences with AI2O3 implantations in humans to bridge resection defects. Journal of Biomedical Materials Research Symposium 6, 227 (1975)
5. Engelhardt, A.: Individual stress calculation by the method of finite elements as basis for orthopaedic operations on the skeleton. Proceedings of the 12th Congress of the International Society of Orthopedic Surgery and Traumatology, Tel Aviv 1972