@article {310407, title = {Timing and probability of ovulation in relation to sex skin swelling in wild West African chimpanzees, Pan troglodytes verus}, journal = {Animal Behaviour}, volume = {66}, year = {2003}, month = {09/2003}, pages = {551-560}, chapter = {551}, author = {Deschnera, T. and Heistermann, M. and Hodgesb, K. and Boesch, C.} }