APA Style
Boo, Elizabeth. (1990).
Ecotourism .
Washington:
WORLD WILDLIFE FUND.
Chicago Style
Boo, Elizabeth.
Ecotourism.
Washington:
WORLD WILDLIFE FUND,
1990.
.
MLA Style
Boo, Elizabeth.
Ecotourism.
Washington:
WORLD WILDLIFE FUND,
1990.
.
Turabian Style
Boo, Elizabeth.
Ecotourism.
Washington:
WORLD WILDLIFE FUND,
1990.
.