Media type: E-Article Title: Dual variational methods and nonvanishing for the nonlinear Helmholtz equation Contributor: Evequoz, Gilles; Weth, Tobias imprint: Elsevier BV, 2015 Published in: Advances in Mathematics Language: English DOI: 10.1016/j.aim.2015.04.017 ISSN: 0001-8708 Origination: Footnote: Access State: Open Access