Barnett, H.L. : Pediatrics, 15th ed. New York, Appleton-Century-Crofts, 1972.
2.
Nelson, W.E.: Textbook of Pediatrics, 9th ed. Philadelphia, W. B. Saunders, 1969 .
3.
Warkany, J.: Congenital Malformations. Chicago, Year Book Medical Publishers, 1971.
4.
Smith, D.W.: Recognizable Patterns of Human Malformations. Volume VII in the Series Major Problems in Clinical Pediatrics. Philadelphia, W. B. Saunders, 1970.
5.
Campbell, H.F. : Pediatric Urology. New York , The MacMillan Company, 1937, p. 324.
6.
Mason-Brown, J.J.: Surgery of Childhood. London, Edward Arnold, 1962, p. 1160
