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
  https://www.jstatsoft.org/v38/i07/.

A BibTeX entry for LaTeX users is

  @Article{mstateJSS2011,
    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},
    doi = {10.18637/jss.v038.i07},
    url = {https://www.jstatsoft.org/v38/i07/},
  }

  Liesbeth C. de Wreede, Marta Fiocco, Hein Putter (2010) The {mstate}
  Package for Estimation and Prediction in Non- and Semi-Parametric
  Multi-State and Competing Risks Models. Computer Methods and Programs
  in Biomedicine, 99, 261-274.

A BibTeX entry for LaTeX users is

  @Article{mstateCompMethods2010,
    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},
  }

  Hein Putter, Marta Fiocco, and Ronald B. Geskus (2007) Tutorial in
  Biostatistics: Competing Risks and Multi-State Models. Statistics in
  Medicine, 26, 2389-2340.

A BibTeX entry for LaTeX users is

  @Article{mstateTutorial2007,
    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},
  }