In this paper, some existence and multiplicity results involving eigenvalues are established for a class of degenerate quasilinear elliptic system by using Ekeland's variational principle, the mountain pass theorem and the critical point theory.
"Existence and multiplicity results for a class of degenerate quasilinear elliptic systems." Bull. Belg. Math. Soc. Simon Stevin 21 (5) 769 - 785, december 2014. https://doi.org/10.36045/bbms/1420071853