1. Acheson, R. M. (1954).J. Anat., 88, 498–508.
2. ————— (1957).Clin. Orthopaedics, 10, 19–39.
3. ----- (1958).Irish J. Med. Sci., Jan., 29–36.
4. Blechschmidt, E. (1951).Z. Anat. Entw., 115, 529–40 and 597–616.
5. Caffey, J.Pediatric X-ray Diagnosis. Year Book Pub., Chicago, 3rd ed., (1956).