To cite touch in publications use:

  Wang, W., Li, Y., Yan, J. (2018). touch: Tools of Utilization and
  Cost in Healthcare. R package version 0.1-6
  https://CRAN.R-project.org/package=touch

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {{touch}: {T}ools of Utilization and Cost in Healthcare},
    author = {Wenjie Wang and Yan Li and Jun Yan},
    note = {{R} package version 0.1-6},
    year = {2018},
    url = {https://CRAN.R-project.org/package=touch},
  }