Ivanchov, N. I., and N. M. Hryntsiv. “Inverse Problem for the Strongly Degenerate Heat Equation in a Domain With Free Boundary”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 61, no. 1, Jan. 2009, pp. 28-43, https://umj.imath.kiev.ua/index.php/umj/article/view/2998.