Butsan , G. P., and K. N. Lyatambur. “Primary Multiplicative Systems of Almost Linear Operators for Almost Linear Additive Operator System Without Continuity Conditions”. Ukrains’kyi Matematychnyi Zhurnal 40, no. 6 (November 1, 1988): 717–724. Accessed December 6, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/9280.