Archer, Michael Dan. «Derby Sculpture». archersculpture.co.uk. Arxivat de l'original el 2011-06-04. [Consulta: 5 gener 2011].
archive.org
Arnold Bemrose, H.H.. Derbyshire (en anglès). Cambridge University Press, 1910, p. 172 [Consulta: 23 desembre 2010]. «In 1896, the author and Mr R.M. Deeley obtained the greater portion of the skeleton of a hippopotamus, together with part of the breast-bone of an elephant and of the femur of a rhinoceros, in the Derwent gravel at Allenton, immediately to the south of Derby. These bones are now in the Museum at Derby.»
van Kolfschoten, Th. «The Eemian mammal fauna of central Europe». Netherlands Journal of Geosciences, 79, 2/3, 2000, pàg. 269–281 [Consulta: 2 febrer 2011]. «...the hippopotamus, Hippopotamus amphibius, and the water buffalo, Bubalus murrensis, present in the Eemian fauna, indicate a climate
with relatively high summer temperatures (mean July temperature > 18 °C) and the absence of periods of severe or long-lasting winter frost»
