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Williams, Howell. (1941). Calderas and their Origin. Berkley: University of California Press, 1st edition, 107 pp. Paperback,. University of California.
Cas, R.A.F. and Wright, J.V. (1987). Volcanic Successions; Modern and Ancient; A Geological Approach to Processes, Products and Successions. Allen and Unwin.
Judd, J.W. (1888). Volcanoes; what they are and what they teach. London: Kegan Paul,. Kegan Paul.