International Journal of Mathematical Analysis
This paper is devoted to the establishment of weak conditions for Darboux-Goursat-Beudon (DGB) theorem in order to improve analogous results in [1, 7]. By adapting a technique proposed by  in another setting  via majorant method, we obtain the generalization of DGB theorem.
Terbeche, Mekki, Broderick O. Oluyede.
"Establishment of Weak Conditions for Darboux-Goursat-Beudon Theorem."
International Journal of Mathematical Analysis, 3 (25): 1229-1237.