Não informado. (1970). National Parks and Conservation Magazine. National Parks & Conservation Association.
Chicago-viite (17. p.)Não informado. National Parks and Conservation Magazine. Washington: National Parks & Conservation Association, 1970.
MLA-viite (8. p.)Não informado. National Parks and Conservation Magazine. National Parks & Conservation Association, 1970.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.