Salafsky, Nick, Barbara L. Dugely, and John W. Terborgh. (1993) 1993. “Can Extractive Reserves Save the Rain Forest? An Ecological and Socioeconomic Comparison of Nontimber Forest Product Extraction Systems in Petén, Guatemala, and West Kalimantan, Indonesia”. Conservation Biology 7 (1): 39-52. doi:10.1046/j.1523-1739.1993.07010039.x.