1. G. Avalishvili, M. Avalishvili, and D. Gordeziani, On integral nonlocal boundary-value problem for some partial differential equations, Bull. Georgian Natl. Acad. Sci. (N.S.), 5(1):31–37, 2011.
2. G. Berikelashvili, Finite-difference schemes for some mixed boundary-value problems, Proc. A. Razmadze Math. Inst., 127:77–87, 2001.
3. G. Berikelashvili, On a nonlocal boundary-value problem for two-dimensional elliptic equation, Comput. Methods Appl. Math., 3(1):35–44, 2003. Dedicated to Raitcho Lazarov.
4. G. Berikelashvili, To a nonlocal generalization of the Dirichlet problem, J. Inequal. Appl., 2006, Article ID 93858, 6 pp., 2006.
5. G.K. Berikelashvili and D.G. Gordeziani, On a nonlocal generalization of the biharmonic Dirichlet problem, Differ. Uravn., 46(3):318–325, 2010 (in Russian). English transl.: Differ. Equ., 46(3):321–328, 2010.