We establish the existence of nontrivial solutions to systems of singular Poisson equations in unbounded domains, under some invariance conditions and singular subcritical growth. The proofs rely on a concentration-compactness argument and on a generalized linking theorem due to Krysewski and Szulkin.
"Systems of singular Poisson equations in unbounded domains." Adv. Differential Equations 10 (9) 1035 - 1052, 2005.