BerezovskyA. A., KerefovA. A., and Shkhanukov-LafishevM. Kh. 1993. “Boundary-Value Problems for the Heat Conduction Equation With a Fractional Derivative in the Boundary Conditions. Difference Methods for Numerical Realization of These Problems”. Ukrains’kyi Matematychnyi Zhurnal 45 (9), 1289–1398. https://umj.imath.kiev.ua/index.php/umj/article/view/5932.