1. Agarwal, R.P.: Difference Equations and Inequalities. Dekker, New York (1992)
2. Alsina, C., Ger, R.: On some inequalities results related to the exponential function. J. Inequal. Appl. 2, 373–380 (1998)
3. Amann, H.: Ordinary Differential Equations. Walter de Gruyter, Berlin (1990)
4. Aoki, T.: On the stability of the linear transformation in Banach spaces. J. Math. Soc. Jpn. 2, 64–66 (1950)
5. Appell, J.: Measure of noncompactness, condensing operators and fixed points: an application-oriented survey. Fixed Point Theory 6, 157–229 (2005)