摘要:The aim of this paper is to correct some ambiguities and inaccuracies in Agarwal et al. (Commun. Nonlinear Sci. Numer. Simul. 20(1):59-73, 2015; Adv. Differ. Equ. 2013:302, 2013, doi: 10.1186/1687-1847-2013-302 ) and to present new ideas and approaches for fractional calculus and fractional differential equations in nonreflexive Banach spaces.