“…In particular to have mixed fractional terms on both sides, that is, having fractional integrals or fractional derivatives on the left-and right-hand side respectively, is an important class that is not fully studied in the literature. There are some real difficulties to examine the existence and uniqueness of solutions for these types of equations, and further properties for these types of equations have been studied by few researchers using different techniques (see, for example, [4,9,14] for partial treatment).…”