1. D. Baird (1959 ): inBritish Obstetric and Gynaecological Practice-Obstetrics . 2nd edition . Heinemann, London, pp. 581 , 581 et seq.
2. F. J. Browne, and J. C. M. Browne (1959 ): inBritish Obstetric and Gynaecological Practice-Obstetrics . 2nd edition . Heinemann, London, p. 100 .
3. Anatomical variations in the female pelvis and their effect in labor with a suggested classification