Schiffmann, Christian, et al. “Body Condition Scores in European Zoo Elephants (Elephas Maximus and Loxodonta Africana) – Status Quo and Influencing Factors”. Journal of Zoo and Aquarium Research, vol. 6, no. 3, July 2018, pp. 91-103, doi:10.19227/jzar.v6i3.355.