To cite package ‘NPCD’ in publications use:

Zheng Y, Chiu C (2019). NPCD: Nonparametric Methods for Cognitive Diagnosis. R package version 1.0-11, https://CRAN.R-project.org/package=NPCD.

Corresponding BibTeX entry:

  @Manual{,
    title = {NPCD: Nonparametric Methods for Cognitive Diagnosis},
    author = {Yi Zheng and Chia-Yi Chiu},
    year = {2019},
    note = {R package version 1.0-11},
    url = {https://CRAN.R-project.org/package=NPCD},
  }