van der Hoff, Quay, Johanna C. Greeff, and P. Hendrik Kloppers. “Numerical Investigation into the Existence of Limit Cycles in Two-Dimensional predator–prey Systems”. South African Journal of Science 109, no. 5/6 (May 23, 2013): 6. Accessed November 23, 2024. https://sajs.co.za/article/view/3888.