Groger, K., & Pankov, A. (1996). Meyers type regularity for bounded and almost periodic solutions to nonlinear second order parabolic equations with mixed boundary conditions. Математическая физика, анализ, геометрия, 3(1-2), 46–64. вилучено із http://mag.ilt.kharkiv.ua/index.php/mag/article/view/m03-0046e