APA
World Commission on Protected Areas (WCPA), Adrian P., . (1998). Economic Values of Protected Areas. Cambridge: IUCN Publications Services Unit.
Chicago
World Commission on Protected Areas (WCPA), Adrian Phillps, . 1998. Economic Values of Protected Areas. Cambridge: IUCN Publications Services Unit.
Harvard
World Commission on Protected Areas (WCPA), Adrian P., . (1998). Economic Values of Protected Areas. Cambridge: IUCN Publications Services Unit.
MLA
World Commission on Protected Areas (WCPA), Adrian Phillps, . Economic Values of Protected Areas. Cambridge: IUCN Publications Services Unit. 1998.