“…For more details, see [13,14,16,17,19,20] and reference therein. Many studies on differential equations of fractional order, involving different fractional operators such as Riemann-Liouville fractional derivative [6,9], Caputo fractional derivative [8,24], Hadamard fractional derivative [1,25],Caputo-Hadamard fractional derivative [15,22] and Atangana-Baleanu-Caputo fractional derivative [18] have appeared during the past several years. Moreover, by using many classical fixed-point theorems, several authors presented the existence and stability results for various classes of fractional differential equations, see for example [4,7,8,11,12,23].…”