1. Rectal bleeding in infants and children
2. David, V. C.: Diseases of the Colon and Rectum. In Brennemann's Practice of Pediatrics. Hagerstown, Maryland, W. F. Prior Company, Inc., 1957, vol. 3, chap. 7, p. 30.
3. Generalized Intestinal Polyposis and Melanin Spots of the Oral Mucosa, Lips and Digits
4. Granet, E.: Manual of Proctology. Chicago, The Year Book Publishers, Inc., 1954, p. 160.