To cite xpose4 in publications, use:

Jonsson E , Karlsson MO (1999). “Xpose–an S-PLUS based population pharmacokinetic/pharmacodynamic model building aid for NONMEM.” Computer Methods and Programs in Biomedicine, 58(1), 51-64. doi:10.1016/s0169-2607(98)00067-4.

Keizer RJ, Karlsson MO, Hooker AC (2013). “Modeling and Simulation Workbench for NONMEM: Tutorial on Pirana, PsN, and Xpose.” CPT: Pharmacometrics & Systems Pharmacology, 2(6). doi:10.1038/psp.2013.24.

Corresponding BibTeX entries:

  @Article{,
    title = {Xpose--an S-PLUS based population
      pharmacokinetic/pharmacodynamic model building aid for NONMEM},
    author = {E Niclas Jonsson and Mats O Karlsson},
    journal = {Computer Methods and Programs in Biomedicine},
    volume = {58},
    number = {1},
    pages = {51-64},
    year = {1999},
    doi = {10.1016/s0169-2607(98)00067-4},
  }

  @Article{,
    title = {Modeling and Simulation Workbench for NONMEM: Tutorial on
      Pirana, PsN, and Xpose},
    author = {Ron J Keizer and Mats O Karlsson and Andrew C Hooker},
    journal = {CPT: Pharmacometrics & Systems Pharmacology},
    year = {2013},
    volume = {2},
    number = {6},
    doi = {10.1038/psp.2013.24},
  }