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Alho, J. S.; Herczeg, G.; Laugen, A. «Allen's Rule Revisited: Quantitative Genetics of Extremity Length in the Common Frog Along a Latitudinal Gradient». Journal of Evolutionary Biology, 24, 1, 2011, pàg. 59–70. DOI: 10.1111/j.1420-9101.2010.02141.x. PMID: 20964781.