Chuiko , S., and O. Nesmelova. “Periodic Boundary-Value Problem for a Rayleigh-Type Equation Unsolved With Respect to the Derivative”. *Ukrains’kyi Matematychnyi Zhurnal* 75, no. 10 (October 24, 2023): 1429 - 1440. Accessed December 1, 2023. https://umj.imath.kiev.ua/index.php/umj/article/view/7362.