Willoughby, E. F. (1891). Retrospect of the Successive Epidemics of Cholera in Europe and America, from 1830 to 1890. Trans Epidemiol Soc Lond.
Chicago-tyylinen lähdeviittausWilloughby, Edward F. "Retrospect of the Successive Epidemics of Cholera in Europe and America, From 1830 to 1890." Trans Epidemiol Soc Lond 1891.
MLA-viiteWilloughby, Edward F. "Retrospect of the Successive Epidemics of Cholera in Europe and America, From 1830 to 1890." Trans Epidemiol Soc Lond 1891.
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