Refice, A., Souid, M.S. and Yakar, A. 2021. Some qualitative properties of nonlinear fractional integro-differential equations of variable order. An International Journal of Optimization and Control: Theories & Applications (IJOCTA). 11, 3 (Dec. 2021), 68–78. DOI:https://doi.org/10.11121/ijocta.2021.1198.