Team, S. “Three Solutions for a Class of (p1, . , Pn)-Biharmonic Systems via Variational Methods: Shapour Heidarkhani”. Thai Journal of Mathematics, vol. 10, no. 3, Dec. 2012, pp. 497-15, https://thaijmath2.in.cmu.ac.th/index.php/thaijmath/article/view/336.