1. Bainov, D, Simeonov, P: Integral Inequalities and Applications. Kluwer Academic, Dordrecht (1992)
2. Pachpatte, BG: Inequalities for Differential and Integral Equations. Academic Press, San Diego (1998)
3. Denche, M, Khellaf, H, Smakdji, M: Some new generalized nonlinear integral inequalities for functions of two independent variables. Int. J. Math. Anal. 7(40), 1961-1976 (2013)
4. Denche, M, Khellaf, H, Smakdji, M: Integral inequalities with time delay in two independent variables. Electron. J. Differ. Equ. 2014, 117 (2014)
5. Khan, ZA: On nonlinear integral inequalities of Gronwall type in two independent variables. Appl. Math. Sci. 7(55), 2745-2757 (2013)