1. Banta, J. V., Nichols, O.: Sacral agenesis. J. Bone Jt Surg. 51-A, 693?703 (1969)
2. Cohn, J., Bay-Nielsen, E.: Hereditary defect of the sacrum and coccyx with anterior sacral meningocele. Acta paediat. scand. 58, 268?274 (1969)
3. Fields, G. A., Schwarz, R. H., Dickens, H. O., Tunnessen, W.: Sacral agenesis in the infant of a gestational diabetic. Obstet. and Gynec. 32, 779?781 (1968)
4. Frye, F. L., McFarland, L. Z., Enright, J. B.: Sacrococcygeal agenesis in Swiss mice. Cornell Vet. 54, 487?495 (1964)
5. Highmore, H.: The history of generation, p. 31. London J. Martin (1651)