Edwards, S. N., McLaughlin, W. J., & Ham, S. H. (1999). Comparative Study of Ecotourism Policy in the Americas-1998: Volume III USA and Canada. University of Idaho; Organization of American States.

Edwards, Stephen N., William J. McLaughlin, and Sam H. Ham. Comparative Study of Ecotourism Policy in the Americas-1998: Volume III USA and Canada. Estados Unidos: University of Idaho; Organization of American States, 1999.

Edwards, Stephen N., et al. Comparative Study of Ecotourism Policy in the Americas-1998: Volume III USA and Canada. University of Idaho; Organization of American States, 1999.