1. Bain , D.E. 2002 A model linking energetic effects of whale watching to killer whale ( Orcinus orca ) population dynamics. Friday Harbor (Washington) University of Washington Press
2. Baldus , R. Cauldwell A. 2004 Tourist hunting and its role in development of wildlife management areas in Tanzania. Tanzanian-German Development Cooperation, Dar es Salaam, Tanzania http://www.wildlife-programme.gtz.de/wildlife/download/hunting_wma.pdf
3. The dynamics of an open-access fishery;Bjorndal;Can J Econ,1987
4. Open access harvesting of wildlife: the poaching pit and conservation of endangered species;Bulte;Agric Econ,2003