To cite package 'traj' in publications use:

Sylvestre MP, et al. (2006). Classification of patterns of delirium severity scores over time in an elderly population. International Psychogeriatrics, 18(4), 667-680. doi:10.1017/S1041610206003334.

Leffondree, K. et al. (2004). Statistical measures were proposed for identifying longitudinal patterns of change in quantitative health indicators. Journal of Clinical Epidemiology, 57, 1049-1062. doi : 10.1016/j.jclinepi.2004.02.012.

Corresponding BibTeX entries:

  @Article{,
    title = {Classification of patterns of delirium severity scores
      over time in an elderly population},
    author = {Marie-Pierre Sylvestre and Jane McCusker and Martin Cole
      and Armelle Regeasse and Eric Belzile and Michal Abrahamowicz},
    journal = {International psychogeriatrics},
    volume = {18},
    number = {04},
    pages = {667--680},
    year = {2006},
    publisher = {Cambridge University Press},
    note = {R package version 1.2},
  }

  @Article{,
    title = {Statistical measures were proposed for identifying
      longitudinal patterns of change in quantitative health
      indicators},
    author = {Karen Leffondree and Michal Abrahamowicz and Armelle
      Regeasse and Regeasse Armelle and Gillian A Hawker and Elizabeth
      M Badley and Jane McCusker and Eric Belzile},
    journal = {Journal of clinical epidemiology},
    volume = {57},
    number = {10},
    pages = {1049--1062},
    year = {2004},
    publisher = {Elsevier},
    note = {R package version 1.2},
  }