J. Dahlin, T. I. Kanui, S. N. Wambugu, and K. S. P. Abelson, “The Suspended Formalin Test: A Method Designed for Studying Formalin-Induced Behaviour in the Speke’s Hingeback Tortoise (Kinixys spekii)”, Scand J Lab Anim Sci, vol. 39, no. 1, pp. 11–15, Dec. 2012.