Vasilyeva, A. B. “On Some Periodic Solutions of Singularly Perturbed Parabolic Equations”. Ukrains’kyi Matematychnyi Zhurnal 59, no. 3 (March 25, 2007): 359–369. Accessed April 11, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/3312.