A Fibering Map Approach for a Laplacian System With Sign-Changing Weight   Function
  We prove the existence of at least two positive solutions for the Laplacian system(E?)On a bounded region by using the Nehari manifold and the fibering maps associated with the Euler functional for the system. 
Seyyed Sadegh Kazemipoor and Mahboobeh Zakeri
math.AP