To cite the 'cIRT' R package and methodology in publications use:

  Culpepper, S. A. and Balamuta, J. J. (2015) cIRT: Choice Item
  Response Theory. URL https://cran.r-project.org/package=cIRT.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {{cIRT: Choice Item Response Theory}},
    author = {Steven Andrew Culpepper and James Balamuta},
    year = {2015},
  }

  Culpepper, S. A. & Balamuta, J. J. (In Press). A hierarchical model
  for accuracy and choice on standardized tests, Psychometrika. DOI:
  10.1007/s11336-015-9484-7 URL
  http://link.springer.com/article/10.1007/s11336-015-9484-7

A BibTeX entry for LaTeX users is

  @Article{2015culpepper,
    title = {A Hierarchical Model for Accuracy and Choice on Standardized Tests},
    author = {Steven Andrew Culpepper and James Joseph Balamuta},
    issn = {0033-3123},
    journal = {Psychometrika},
    year = {2015},
    pages = {1--26},
    doi = {10.1007/s11336-015-9484-7},
    url = {http://dx.doi.org/10.1007/s11336-015-9484-7},
    keywords = {high-stakes testing; item response theory; Thurstonian models; Bayesian statistics; choice},
    language = {English},
    publisher = {Springer US},
  }