BigunYa. I. “Averaging of a Multifrequency Boundary-Value Problem With Linearly Transformed Argument”. Ukrains’kyi Matematychnyi Zhurnal 52, no. 3 (March 25, 2000): 291-299. Accessed November 25, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/4419.