Dai-xi, Liao, et al. “Existence and Exponential Stability of Periodic Solution for Fuzzy BAM Neural Networks With Periodic Coefficient”. Ukrains’kyi Matematychnyi Zhurnal, vol. 63, no. 12, Dec. 2011, pp. 1672-84, https://umj.imath.kiev.ua/index.php/umj/article/view/2833.