↑Goin CJ, Goin OB, Zug GR. 1978. Introduction to Herpetology, Third Edition. San Francisco: W.H. Freeman and Company. xi + 378 pp. ISBN0-7167-0020-4. (Genus Callophis [sic], p. 331).
Further reading
Boulenger GA. 1896. Catalogue of the Snakes in the British Museum (Natural History). Volume III., Containing the Colubridæ (Opisthoglyphæ and Proteroglyphæ), ... London: Trustees of the British Museum (Natural History). (Taylor and Francis, printers). xiv + 727 pp. + Plates I-XXV. (Genus Callophis [sic], p.396).
Gray JE. 1834. Illustrations of Indian Zoology; Chiefly Selected from the Collection of Major-General Hardwicke, F.R.S., ... Vol. II. London: Adolphus Richter and Co. 102 plates. (Calliophis gracilis, Plate 86, Figures 1 & 3).
Smith MA. 1943. The Fauna of British India, Ceylon and Burma, Including the Whole of the Indo-Chinese Sub-region. Reptilia and Amphibia. Vol. III.—Serpentes. London: Secretary of State for India. (Taylor and Francis, printers). xii + 583 pp. (Genus Callophis [sic], pp.418–419).