Blow up of solutions for Klein-Gordon equations in the Reissner-Nordstrom metric. Georgiev, Svetlin G. — 2005 Electronic Journal of Differential Equations (EJDE) [electronic only]
An incorrectly posed problem for nonlinear elliptic equations. Georgiev, Svetlin G. — 2009 Electronic Journal of Differential Equations (EJDE) [electronic only]