Martynyuk, A. A., and Y. A. Martynyuk-Chernienko. “Stability of Motion of Nonlinear Systems With Fuzzy Characteristics of Parameters”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 64, no. 1, Jan. 2012, pp. 50-70, https://umj.imath.kiev.ua/index.php/umj/article/view/2555.