To cite mstate in publications use:

Liesbeth C. de Wreede, Marta Fiocco, Hein Putter (2011). mstate: An R Package for the Analysis of Competing Risks and Multi-State Models. Journal of Statistical Software, 38(7), 1-30. URL http://www.jstatsoft.org/v38/i07/.
Liesbeth C. de Wreede, Marta Fiocco, Hein Putter (2009) The {mstate} Package for Estimation and Prediction in Non- and Semi-Parametric Multi-State and Competing Risks Models. Submitted to Computer Methods and Programs in Biomedicine.
Hein Putter, Marta Fiocco, and Ronald B. Geskus (2007) Tutorial in Biostatistics: Competing Risks and Multi-State Models. Statistics in Medicine, 26, 2389-2340.

Corresponding BibTeX entries:

  @Article{,
    title = {{mstate}: An {R} Package for the Analysis of Competing
      Risks and Multi-State Models},
    author = {Liesbeth C. de Wreede and Marta Fiocco and Hein Putter},
    journal = {Journal of Statistical Software},
    year = {2011},
    volume = {38},
    number = {7},
    pages = {1--30},
    url = {http://www.jstatsoft.org/v38/i07/},
  }
  @Article{,
    title = {The {mstate} Package for Estimation and Prediction in Non-
      and Semi-Parametric Multi-State and Competing Risks Models},
    author = {Liesbeth C. de Wreede and Marta Fiocco and Hein Putter},
    journal = {Computer Methods and Programs in Biomedicine},
    year = {2010},
    volume = {99},
    pages = {261--274},
  }
  @Article{,
    title = {Tutorial in Biostatistics: Competing Risks and Multi-State
      Models},
    author = {Hein Putter and Ronald B. Geskus and Marta Fiocco},
    journal = {Statistics in Medicine},
    year = {2007},
    number = {26},
    pages = {2389--2430},
  }