Wich, S. A., Sterck, E. H. M. and Utami, S. S. (1999) Are orangutan females as solitary as chimpanzee females? Folia Primatologica 70: 23-28.

Wich, S. A., Steenbeek, R., Sterck, E. H. M., Palombit, R. A. and Usman, S. (1999) Tree mortality and recruitment in an Indonesian rainforest. Tropical Biodiversity 6(3): 189-195.

Wich, S. A. and van Schaik, C.P.van. (2000) The impact of El Niño on mast fruiting in Sumatra and elsewhere in Malesia Journal of Tropical Ecology 16 (4), 563-577.

Wich, S. A. (2002) The Structure and Function of Thomas langur Loud Calls. PhD-Thesis, Utrecht University

Wich, S. A., Assink, P. R., Becher, F. and Sterck, E. H. M. (2002) Playbacks of loud calls to wild Thomas langurs (Primates; Presbytis thomasi): the effect of location. Behaviour 139: 65-78.

Wich, S. A., Assink, P. R., Becher, F. and Sterck, E. H. M. (2002) Playbacks of loud calls to wild Thomas langurs (Primates; Presbytis thomasi): the effect of familiarity. Behaviour 139: 79-87.

Wich, S. A., Fredriksson, G., Sterck, E. H. M. (2002) Measuring fruit patch size availability for three sympatric Indonesian primates. Primates 43(1): 19-27.

Wich, S. A. and Nunn, C. L. (2002) Do male "long-distance calls" function in mate defense? A comparative study of long-distance calls in primates. Behavioural Ecology and Sociobiology 54:474-484.

Wich, S. A., Koski, S. , de Vries, H. and van Schaik, C. P.(2003) Individual and contextual variation in Thomas langur male loud calls. Ethology 109: 1-13.

Wich, S. A., Singleton, I., Utami-Atmoko, S. S., Geurts, M. L., Rijksen, H. D. and van Schaik, C. P. (2003) The status of the Sumatran Orangutan Pongo abelii: an update. Oryx 37 (1): 49-54.

Wich, S. A. and Sterck, E. H. M. (2003). Possible audience effect in Thomas langurs (Primates; Presbytis thomasi): An experimental study on male loud calls in response to a tiger model. American Journal of Primatology 60:155-159.

Wich, S. A., van de Post, D. J., Heistermann, M., Möhle, M., van Hooff, J. A. R. A. M., Sterck, E. H. M. (2003) Tenure Related Changes in Male Loud Call Characteristics and Testosterone Levels in Wild Thomas Langurs. International Journal of Primatology 24: 1251-1265.

Wich, S. A., Assink, P. R., and Sterck, E. H. M. (2004). Thomans langurs (Presbytis thomasi) discriminate between calls of young solitary versus older group-living males: a factor in avoiding infanticide? Behaviour 141: 41-51

Wich, S. A., Buij, R., and van Schaik, C. P. (2004). Determinants of orangutan density in the dryland forests of the Leuser Ecosystem. Primates 45:177-182

Wich, S. A.., Utami-Atmoko, S. S., Mitra Setia, T., Rijksen, H. R., Schürmann, C., van Hooff, J. A. R. A. M., and van Schaik, C. P. (2004). Life history of wild Sumatran orangutans (Pongo abelii). Journal of Human Evolution 47: 385-398

Graaf, B. de., Bos, J. E., Wich, S. and Bles, W. (1994) Arthrokinetic and vestibular information enhance smooth ocular tracking during linear (self) motion. Experimental Brain Research 101: 147-152.

Utami, S., Wich, S. A., Sterck, E, H, M. and Hooff, J. A. R. A. M. van. (1997) Food competition between wild orangutans in large fig trees. International Journal of Primatology 18 (6): 909-927.

Steenbeek, R., Assink, P. and Wich, S.A. (1999) Tenure related changes in wild Thomas's langurs II: loud calls. Behaviour 136: 627-650.

Buij, R., Wich, S. A., Lubis, A. H., and Sterck, E. H. M. (2002) Seasonal movements in the Sumatran orangutan (Pongo pygmaeus abelii) and consequences for conservation. Biological Conservation 107: 83-87.

Knop, E., Ward, P. I. and Wich, S. A. (2004). Comparing orangutan density in a logged and unlogged forest on Sumatra. Biological Conservation 120: 183-188.

Boubli, J. P., Eriksson, J., Wich, S. A., Hohmann, G. and Fruth, B. (2004). Mesoscale Tree Inventory of the Lomako-Yekokora Interfluvium, Democratic Republic of the Congo. Biodiversity and Conservation 13: 2399-2417

Van Schaik, C. P., Wich, S. A., Utami, S. S. & Odom, K. (2005) A simple method alternative to line transects of nests for estimating orangutan densities. Primates 46:249-254

Wich, S.A. & de Vries, H. (2006) Male monkeys remember which group members have given alarm calls. Proceedings of the Royal Society B 273: 735-740