Geometry and topology of the boundary in the critical Neumann problem. G. Mancini; Adimurthi — 1994 Journal für die reine und angewandte Mathematik
Elliptic Equations with Noninvertible Fredholm Linear Part and Bounded Nonlinearities. H. Amann; A. Ambrosett; G. Mancini — 1978 Mathematische Zeitschrift