@article{ThielRomanoSchwarzetal.2001,
  author    = {Marco Thiel and Maria Carmen Romano and Udo Schwarz and J{\"u}rgen Kurths and G{\"u}nther Hasinger and Tomaso Belloni},
  title     = {Nonlinear Time series analysis of the X-ray flux of compact objects},
  year      = {2001},
}