Machlis, G. E., & Tichnell, D. L. (1985). The state of the world's parks: An international assessment for resource management, policy, and research. Westview Press.
Chicago-referens (17:e uppl.)Machlis, Gary E., och David L. Tichnell. The State of the World's Parks: An International Assessment for Resource Management, Policy, and Research. Boulder, Colo: Westview Press, 1985.
MLA-referens (9:e uppl.)Machlis, Gary E., och David L. Tichnell. The State of the World's Parks: An International Assessment for Resource Management, Policy, and Research. Westview Press, 1985.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.