To cite cNORM in publications you can either refer to Package itself or to one or several of the primary sources:

Lenhard A, Lenhard W, Gary S (2018). Continuous Norming (cNORM). https://CRAN.R-project.org/package=cNORM.

Lenhard A, Lenhard W, Suggate S, Segerer R (2018). “A continuous solution to the norming problem.” Assessment, 25(1), 112–125. https://journals.sagepub.com/doi/10.1177/1073191116656437.

Lenhard A, Lenhard W, Gary S (2019). “Continuous norming of psychometric tests: A simulation study of parametric and semi-parametric approaches.” PloS One, 14(9). https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0222279.

Lenhard W, Lenhard A (2020). “Improvement of Norm Score Quality via Regression-Based Continuous Norming.” Educational and Psychological Measurement, Online First, 1-33. https://journals.sagepub.com/doi/full/10.1177/0013164420928457.

Corresponding BibTeX entries:

  @Manual{,
    title = {Continuous Norming (cNORM)},
    author = {Alexandra Lenhard and Wolfgang Lenhard and Sebastian
      Gary},
    journal = {The Comprehensive R Archive Network},
    year = {2018},
    url = {https://CRAN.R-project.org/package=cNORM},
  }

  @Article{,
    title = {A continuous solution to the norming problem},
    author = {Alexandra Lenhard and Wolfgang Lenhard and Sebastian
      Suggate and Robin Segerer},
    journal = {Assessment},
    year = {2018},
    volume = {25},
    number = {1},
    pages = {112--125},
    url = {https://journals.sagepub.com/doi/10.1177/1073191116656437},
  }

  @Article{,
    title = {Continuous norming of psychometric tests: A simulation
      study of parametric and semi-parametric approaches},
    author = {Alexandra Lenhard and Wolfgang Lenhard and Sebastian
      Gary},
    journal = {PloS One},
    year = {2019},
    volume = {14},
    number = {9},
    url =
      {https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0222279},
  }

  @Article{,
    title = {Improvement of Norm Score Quality via Regression-Based
      Continuous Norming},
    author = {Wolfgang Lenhard and Alexandra Lenhard},
    journal = {Educational and Psychological Measurement},
    year = {2020},
    volume = {Online First},
    pages = {1-33},
    url =
      {https://journals.sagepub.com/doi/full/10.1177/0013164420928457},
  }