MBoro NChama, G. A. “A Theoretical Improvement of the Riemann-Liouville and Caputo Fractional Derivatives”. Divulgaciones Matemáticas, Vol. 21, no. 1-2, Dec. 2020, pp. 33-41, https://produccioncientifica.luz.edu.ve/index.php/divulgaciones/article/view/36602.