1. American Cancer Society. Cancer Facts and Figures 1997. Atlanta, GA: American Cancer Society.
2. Vitamin A and lung cancer;Willett;Nutr Rev,1990
3. Cancer incidence in Louisiana, 1988–1992;Chen,1996
4. Fruit, vegetable and cancer prevention;Block;Nutr Cancer,1992
5. Fruit and vegetable consumption;Patterson,1991