APA Citation

IUCN. (1973). A System for defining and classifying natural regions for purposes of conservation. [S.l.]: [s.n.].

Chicago Style Citation

IUCN. A System for Defining and Classifying Natural Regions for Purposes of Conservation. [S.l.]: [s.n.], 1973.

MLA Citation

IUCN. A System for Defining and Classifying Natural Regions for Purposes of Conservation. [S.l.]: [s.n.], 1973.

Warning: These citations may not always be 100% accurate.