1. Cannon, J.R., The Solution of the Heat Equation Subject to the Specification of Energy, Quart. Appl. Math., 1963, vol. 21, no. 2, pp. 155–160.
2. Karaushev, A.V., Rechnaya gidravlika (Fluvial Hidraulics), Leningrad, 1969.
3. Alekseev, A.S. and Kirillov, Yu.P., Investigation of a Class of Partial Differential Equations with Integral Boundary Conditions, Diff. Integr. Uravn., Gorkii, 1979, no. 3, pp. 118–122.
4. Sapagovas, M.P., A Difference Scheme for Two-Dimensional Elliptic Problems with an Integral Condition, Litovsk. Mat. Sb., 1983, vol. 23, no. 3, pp. 155–159.
5. Paneyakh, B.P., Some Nonlocal Boundary Value Problems for Linear Differential Operators, Mat. Zametki, 1984, vol. 35, no. 3, pp. 425–434.