Kirjackis, J., and E. G. Kiriyatzkii. “Linearly Invariant Classes of Functions Analytical in the Half-Plane”. Nonlinear Analysis: Modelling and Control 9, no. 4 (October 25, 2004): 349–361. Accessed April 21, 2025. https://www.zurnalai.vu.lt/nonlinear-analysis/article/view/15149.