%0 Journal Article %J Animal Behaviour %D 2003 %T Timing and probability of ovulation in relation to sex skin swelling in wild West African chimpanzees, Pan troglodytes verus %A Deschnera, T. %A Heistermann, M. %A Hodgesb, K. %A Boesch, C. %B Animal Behaviour %V 66 %P 551-560 %8 09/2003 %G eng %N 3 %& 551