Bernatskaya, J. N. “On the Behavior of a Simple-Layer Potential for a Parabolic Equation on a Riemannian Manifold”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 60, no. 7, July 2008, pp. 879–891, https://umj.imath.kiev.ua/index.php/umj/article/view/3206.