@article{16499,
  author       = {{Biasco, Luca and Di Gregorio, Laura}},
  issn         = {{0003-9527}},
  journal      = {{Archive for Rational Mechanics and Analysis}},
  pages        = {{303--362}},
  title        = {{{A Birkhoff–Lewis Type Theorem for the Nonlinear Wave Equation}}},
  doi          = {{10.1007/s00205-009-0240-y}},
  year         = {{2009}},
}

@article{16634,
  author       = {{Melbourne, Ian and Dellnitz, Michael and Golubitsky, Martin}},
  issn         = {{0003-9527}},
  journal      = {{Archive for Rational Mechanics and Analysis}},
  pages        = {{75--98}},
  title        = {{{The structure of symmetric attractors}}},
  doi          = {{10.1007/bf00386369}},
  year         = {{1993}},
}