On Periodic Solutions for Implicit Problem with Nonlinear Fractional Differential Equation Involving the Riesz-Caputo Fractional Derivative. Lett. Nonlinear Anal. Appl. [Internet]. 2026 Mar. 31 [cited 2026 May 14];4(1):44-59. Available from: https://lettersinnonlinearanalysis.com/index.php/lnaa/article/view/74