Brown, Wallace L.
WW. Norton and Company, 1961
Buku Teks
Howitt, William
Sydney University Press, 1972
Buku Teks
Siregar, Gontar Alamsyah, author
The Indonesian Journal of Gastroenterology Hepatology and Digestive Endoscopy, 2003
Artikel Jurnal
P. F. Collier & Son Corporation, 1959 ; 1969
Buku Referensi
Artikel Jurnal