Vigilance in wild Thomas's langurs ( Presbytis thomasi ): the importance of infanticide risk.Published in:Behavioral Ecology & Sociobiology, 1999, v. 45, n. 2, p. 137, doi. 10.1007/s002650050547By:Steenbeek, Romy;Piek, Ruben C.;van Buul, Marleen;van Hooff, Jan A. R. A. M.Publication type:Article