The sub-supersolution method for variable exponent double phase systems with nonlinear boundary conditions. (English) Zbl 1534.35150
Atti Accad. Naz. Lincei, Cl. Sci. Fis. Mat. Nat., IX. Ser., Rend. Lincei, Mat. Appl. 34, No. 3, 617-639 (2023).