[1]
Y. M. Berezansky, Y. A. Mitropolskiy, and M. K. Shkhanukov-Lafishev, “Stabilization for a finite time in problems with free boundary for some classes of nonlinear second-order equations”, Ukr. Mat. Zhurn., vol. 51, no. 2, pp. 214–223, Feb. 1999.