1. R.P. Agarwal, On finite systems of difference inequalities. J. Math. Phys. Sci. 10 (4), 277–288 (1976)
2. R.P. Agarwal, E. Thandapani, On some new discrete inequalities. Appl. Math. Comput. 7, 205–244 (1980)
3. R.P. Agarwal, E. Thandapani, On discrete generalizations of Gronwall’s inequality. Bull. Inst. Math. Acad. Sin. 9, 235–248 (1981)
4. V.M. Alekseev, An estimate for the perturbation of the solutions of ordinary differential equations. Vestnik Moskov. Univ. Ser. I. Mat. Meh. (Russian) 2, 28–36 (1961)
5. S. Asirov, Ja. D. Mamedov, Investigation of solutions of nonlinear Volterra-Fredholm operator equations. Dokl. Akad. Nauk SSSR, 229, 982–986 (1976)