Team, S. “Coincidence Point Theorem on Hilbert Spaces via Weak Ekeland Variational Principle and Application to Boundary Value Problem: Mehdi Asadi, Erdal Karapinar”. Thai Journal of Mathematics, vol. 19, no. 1, Mar. 2021, pp. 1–7, https://thaijmath2.in.cmu.ac.th/index.php/thaijmath/article/view/1129.