Imanbaev, N.S., and B.E. Kanguzhin. “On Spectral Question of the Cauchy-Riemann Operator With Homogeneous Boundary Value Conditions”. Bulletin of the Karaganda University. Mathematics Series 90, no. 2 (June 30, 2018): 49–55. Accessed August 23, 2025. http://mts.buketov.edu.kz/index.php/mathematics-vestnik/article/view/209.