@article{Hayes1995,
author = {Hayes, R.J. and Schulz, K.F. and Plummer, F.A.},
title= {The cofactor effect of genital ulcers on the per-exposure risk of HIV transmission in sub-Saharan Africa},
year = {1995},
journal = {Journal of Tropical Medicine and Hygiene},
volume = {98},
pages = {1--8},
}