@article{StarkFeudelGlendinningetal.2002,
  author    = {Stark, J. and Feudel, Ulrike and Glendinning, P. A. and Pikovskij, Arkadij},
  title     = {Rotation numbers for quasi-periodically forced monotone circle maps},
  issn      = {1468-9367},
  year      = {2002},
  language  = {en}
}
@article{GlendinningFeudelPikovskijetal.2000,
  author    = {Glendinning, P. A. and Feudel, Ulrike and Pikovskij, Arkadij and Stark, J.},
  title     = {The structure of mode-locking regions in quasi-periodically forced circle maps},
  year      = {2000},
  language  = {en}
}