Oprzędkiewicz, Krzysztof. “The Positivity of the Fractional Order Model of a Two-Dimensional Temperature Field”. Bulletin of the Polish Academy of Sciences Technical Sciences 71, no. 4 (June 30, 2023): e145675. Accessed August 30, 2026. https://wydawnictwo.pan.pl/index.php/bpasts/article/view/3553.