1. World Health Organization. Causes of deaths by sex and age. In: World Health Statistics Annula. WHO, Geneva. : WHO; 1993;.
2. Omata M. Current perspectives on hepatocellular carcinoma in Oriental and African countries compared to developed western countries. Dig Dis 1987;5:97-115.
3. Simonetti RG, Cammà C, Fiorello F, Politi F, D'Amico G, Pagliaro L. Hepatocellular carcinoma. A worldwide problem and the major risk factors. Dig Dis Sci 1991;36:962-972.
4. Szmuness W. Hepatocellular carcinoma and the hepatitis B virus: evidence for a causal association. Prog Med Virol 1978;24:40-69.
5. Beasley RP. Hepatitis B virus as the etiologic agent in hepatocellular carcinoma epidemiologic considerations. Hepatology 1982;2:21S-27S.