-. (1989). Nature's wonderlands: National park of the world. National geography society.
Chicago (17e ed.) Bronvermelding-. Nature's Wonderlands: National Park of the World. Washington: National geography society, 1989.
MLA (9e ed.) Bronvermelding-. Nature's Wonderlands: National Park of the World. National geography society, 1989.
Let op: Deze citaties zijn niet altijd 100% accuraat.