Hedström, Ingemar, Andrew Denzel, y Gareth Owens. «Orchid Bees As Bio-Indicators for Organic Coffee Farms in Costa Rica: Does Farm Size Affect Their Abundance?». Revista de Biología Tropical 54, no. 3 (septiembre 1, 2006): 965–969. Accedido agosto 16, 2024. https://revistas.ucr.ac.cr/index.php/rbt/article/view/14075.