n th order neutral differential equations with properties A W and B W . Grammatikopoulos, M.K.; Koplatadze, R. — 2000 Georgian Mathematical Journal
On the oscillation of solutions of first-order differential equations with retarded arguments. Grammatikopoulos, M.K.; Koplatadze, R.; Stavroulakis, I.P. — 2003 Georgian Mathematical Journal
New singular solutions of Protter's problem for the 3D wave equation. Grammatikopoulos, M.K.; Popivanov, N.I.; Popov, T.P. — 2004 Abstract and Applied Analysis