Underwood, G. (1967). A contribution to the classification of snakes. British Museum (Natural History).
Chicago Style (17. basım) AtıfUnderwood, Garth. A Contribution to the Classification of Snakes. London: British Museum (Natural History), 1967.
MLA (8th ed.) AtıfUnderwood, Garth. A Contribution to the Classification of Snakes. British Museum (Natural History), 1967.
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