VoinaO. A., and SidorovM. V. “Equations of Optimal Nonlinear Filtration and Interpolation for Partially Observed Markov Processes”. Ukrains’kyi Matematychnyi Zhurnal 46, no. 8 (August 25, 1994): 971–976. Accessed September 1, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/5649.