BoichukО. A., and PokutnyiО. О. “Application of the Ergodic Theory to the Investigation of a Boundaryvalue Problem With Periodic Operator Coefficient”. Ukrains’kyi Matematychnyi Zhurnal 65, no. 3 (March 25, 2013): 329-338. Accessed April 27, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2422.