[1] E.A. de Barros e Silva, Existence and multiplicity of solutions for semilinear elliptic systems, NoDEA Nonlinear Differential Equations Appl. 1 (1994) 339–363.
[2] Ph. Clément, D.G. de Figueiredo, E. Mitidieri, Positive solutions of semilinear elliptic systems, Comm. Partial Differential Equations 17 (1992) 923–940.
[3] R. Dalmasso, Existence and uniqueness of positive solutions of semilinear elliptic systems, Nonlinear Anal. 39 (2000) 559–568.
[4] D.G. De Figueiredo, Nonlinear elliptic systems, An. Acad. Bras. Ciênc. 72 (4) (2000) 453–469.
[5] M. Ghergu, V. Radulescu, Explosive solutions of semilinear elliptic systems with gradient term, RACSAM Rev. R. Acad. Cienc. Exactas Fis. Nat. Ser. A ˘ Mat. 97 (3) (2003) 467–475.
[6] P. Jebelean, R. Precup, Solvability of p, q-Laplacian systems with potential boundary conditions, Appl. Anal. 89 (2010) 221–228.
[7] D. Muzsi, R. Precup, Nonresonance and existence for systems of nonlinear operator equations, Appl. Anal. 87 (9) (2008) 1005–1018.
[8] J.M. Ortega, W.C. Rheinboldt, Iterative Solution of Nonlinear Equations in Several Variables, Academic Press, New York, 1970.
[9] R. Precup, The Leray–Schauder condition in critical point theory, Nonlinear Anal. 71 (2009) 3218–3228.
[10] R. Precup, The role of matrices that are convergent to zero in the study of semilinear operator systems, Math. Comput. Modelling 49 (2009) 703–708.
[11] R. Precup, Existence, localization and multiplicity results for positive radial solutions of semilinear elliptic systems, J. Math. Anal. Appl. 352 (2009)48–56.
[12] R. Precup, A. Viorel, Existence results for systems of nonlinear evolution equations, Int. J. Pure Appl. Math. 47 (2008) 199–206.
[13] F. Robert, Matrices non-negatives et normes vectorielles (Cours de D.E.A.), Université Scientifique et Médicale, Lyon, 1973.
[14] M. Schechter, Linking Methods in Critical Point Theory, Birkhäuser, Basel, 1999.
[15] J. Serrin, H. Zou, The existence of positive entire solutions of elliptic Hamiltonian systems, Comm. Partial Differential Equations 23 (1998) 577–599.