IBRAHIM , Rabha W., Sugumaran HARIKRISHNAN, and Kuppusamy KANAGARAJAN. “Existence and Stability of Langevin Equations With Two Hilfer-Katugampola Fractional Derivatives”. Studia Universitatis Babeș-Bolyai Mathematica 63, no. 3 (September 20, 2018): 291–302. Accessed August 29, 2025. https://studia.reviste.ubbcluj.ro/index.php/subbmathematica/article/view/2081.