@article{MandelScheiderYeşil2021,
  author    = {Rainer Mandel and Dominic Scheider and Tolga Ye{\c{s}}il},
  title     = {Dual variational methods for a nonlinear Helmholtz equation with sign-changing nonlinearity},
  journal   = {Calculus of variations and partial differential equations},
  volume    = {60},
  number    = {art. 133},
  pages     = {1 -- 13},
  doi       = {10.1007/s00526-021-02006-5},
  year      = {2021},
}