Boundary singularities of positive solutions of some nonlinear elliptic   equations
  We study the behaviour near a boundary point a of any positive solution of a nonlinear elliptic equations with forcing term which vanishes on the boundary except at a. Our results are based upon a priori estimates for solutions and existence or non existence and uniqueness results for solutions of some nonlinear elliptic equations on the half unit sphere. 
Marie-Francoise Bidaut-Veron, Augusto Ponce, Laurent Veron