[1] A. Aghajani, J. Shamshiri, Multiplicity of positive solutions for quasilinear elliptic p-Laplacian systems, Electron. J. Differential Equations No. 111 (2012), 1–16.
[2] C. Azizieh, Ph. Clement. A priori estimates and continuation methods for positive solutions of p-Laplace equations, J. Differential Equations 179 (2002), 213-245.
[3] C. Azizieh, Ph. Clement, E. Mitidieri, Existence and a priori estimates for positive solutions of p-Laplace systems, J. Differential Equations 184 (2002), 422–442.
[4] Ph. Clement, J. Fleckinger, E. Mitidieri, F. de Thelin, Existence of positive solutions for a nonvariational quasilinear elliptic system, J. Differential Equations 166 (2000), 455–477.
[5] Ph. Clement, M. Garcıa-Huidobro, I. Guerra, R. Manasevich, On regions of existence and nonexistence of solutions for a system of p-q-Laplacians, Asymptot. Anal. 48 (2006), 1–18.
[6] K. Deimling, Nonlinear Functional Analysis, Springer, Berlin, 1985.
[7] S. El Manouni, K. Perera, R. Shivaji, On singular quasi-monotone (p, q)-Laplacian systems, Proc. Roy. Soc. Edinburgh Sect. A 142 (1012), 585–594.
[8] J. Fleckinger, J.-P. Gossez, P. Takac, F. de Thelin, Existence, nonexistence et principe de l’antimaximum pour le p-laplacien, C. R. Acad. Sci. Paris S´er. I Math. 321 (1995), 731–734.
[9] J. Giacomoni, J. Hernandez, A. Moussaoui, Quasilinear and singular systems: the cooperative case. In Nonlinear elliptic partial differential equations, volume 540 of Contemp. Math., pages 79–94. Amer. Math. Soc., Providence, RI, 2011.
[10] A. Granas, J. Dugundji, Fixed Point Theory, Springer, New York, 2003.
[11] D. D. Hai, R. Shivaji, An existence result on positive solutions for a class of p-Laplacian systems, Nonlinear Anal. 56 (2004), 1007–1010.
[12] D. D. Hai, H. Wang, Nontrivial solutions for p-Laplacian systems, J. Math. Anal. Appl. 330 (2007), 186–194.
[13] G. Infante, P. Pietramala, Existence and multiplicity of non-negative solutions for systems of perturbed Hammerstein integral equations, Nonlinear Anal. 71 (2009), 1301–1310.
[14] P. Jebelean, R. Precup, Solvability of p, q-Laplacian systems with potential boundary conditions, Appl. Anal. 89 (2010), 221–228.
[15] J. Jost, Partial Differential Equations, Springer-Verlag, New York, 2002.
[16] K. Q. Lan, Z. Zhang, Nonzero positive weak solutions of systems of p-Laplace equations, J. Math. Anal. Appl. 394 (2012), 581–591.
[17] P. Lindqvist, Notes on the p-Laplace equation, Report 102. University of Jyv¨askyl¨a Department of Mathematics and Statistics, University of Jyv¨askyl¨a, Jyv¨askyl¨a, 2006.
[18] L. Montoro, B. Sciunzi, M. Squassina, Symmetry results for nonvariational quasi-linear elliptic systems, Adv. Nonlinear Stud. 10 (2010), 939–955.
[19] R. Precup, Moser-Harnack inequality, Krasnosel’skii type fixed point theorems in cones and elliptic problems, Topol. Methods Nonlinear Anal. 40 (2012), 301–313.
[20] R. Precup, Abstract weak Harnack inequality, multiple fixed points and p-Laplace equations, J. Fixed Point Theory Appl. 12 (2012), 193–206.
[21] Y. Shen, J. Zhang, Multiplicity of positive solutions for a semilinear p-Laplacian system with Sobolev critical exponent, Nonlinear Anal. 74 (2011), 1019–1030.
[22] N. S. Trudinger, On Harnack type inequalities and their applications to quasilinear elliptic. Comm. Pure Appl. Math. 20 (1967), 721–747.
[23] H. Wang, Existence and nonexistence of positive radial solutions for quasilinear systems, Discrete Contin. Dyn. Syst. suppl. (2009), 810–817.
[24] J. R. L. Webb, K. Q. Lan, Eigenvalue criteria for existence of multiple positive solutions of nonlinear boundary value problems of local and nonlocal type, Topol. Methods Nonlinear Anal. 27 (2006), 91–115.
[25] L. Wei, Z. Feng, Existence and nonexistence of solutions for quasilinear elliptic systems, Dyn. Partial Differ. Equ. 10 (2013), 25–42.