1) Padian, N. S., Shiboski, S. C. & Jewell, N. P.: Female-to-male transmission of human immunodeficiency virus. J. A. M. A., 266: 1664-1667, 1991.
2) Plummer, F. A., Simonsen, J. N., Cameron, D. W., Nidinya-Waiyaki, J. O., Kreiss, J. K., Gakinya, M. N., Waiyaki, P., Cheang, M., Piot, P., Ronald, A. R. & Ngugi, E. N.: Cofactors in Male-to-female sexual transmission of human immunodeficiency virus type-l. J. Infect. Dis., 163: 233-239, 1991.
3) Mann, J. M., Nzilambi, N., Piot, P., Bosenge, N., Kalala, M., Fransis, H., Colebunders, R. C., Kasa Azila, P., Curran, J. W. & Quinn, T. C.: Hiv infection and associated risk factor in female prostitute in Kinshasa, Zaire. AIDS., 2: 249-254, 1988.
4) Kreiss, J. K., Koech, D., Plummer, F. A., Holmes, K. K., Lightfoot, M., Piot, P., Ronald, A. R., Ndinya-Achola, J. O., D'Costa, J., Roberts, P., Ngugi, E. N. & Quinn, T. C.: AIDS virus infection in Nairobi prostitute: Spread of the epidemic to east Africa. New Engl. J. Med., 314: 414-418, 1986.
5) Wasserheit, J. N. & Hitchcock, P. J.: Sexually transmitted diseases, Quinn TC eds. Advances in host defence mechanisms, New York: Raven Press, 1992.