Mitropolskiy, Yu. A. “On the Construction of an Asymptotic Solution of a Perturbed Bretherton Equation”. Ukrains’kyi Matematychnyi Zhurnal 50, no. 1 (January 25, 1998): 58–71. Accessed February 17, 2026. https://umj.imath.kiev.ua/index.php/umj/article/view/4972.