Szulkin, Andrzej: Generalized linking theorem and nonlinear equations in unbounded domains.
(English).
In:
Agarwal, Ravi P., Neuman, F.
and Vosmanský, J. (eds.): Proceedings of Equadiff 9, Conference on Differential Equations and Their Applications, Brno, August 25-29, 1997.
[Part 1] Survey papers.
Masaryk University, Brno, 1998.
pp. 159-168