APA (7th ed.) Citation

Unsworth, W. (1977). Encyclopedia of mountaineering ([Revised ed.].). Penguin.

Chicago Style (17th ed.) Citation

Unsworth, Walt. Encyclopedia of Mountaineering. [Revised ed.]. Harmondsworth ; New York: Penguin, 1977.

MLA (8th ed.) Citation

Unsworth, Walt. Encyclopedia of Mountaineering. [Revised ed.]. Penguin, 1977.