To cite package 'hmmm' in publications use:

Colombi R, Giordano S, Cazzaro M (2014). “hmmm: An R Package for Hierarchical Multinomial Marginal Models.” Journal of Statistical Software, 59(11), 1–25. https://www.jstatsoft.org/article/view/v059i11.

Corresponding BibTeX entry:

  @Article{,
    title = {{hmmm}: An {R} Package for Hierarchical Multinomial
      Marginal Models},
    author = {Roberto Colombi and Sabrina Giordano and Manuela
      Cazzaro},
    journal = {Journal of Statistical Software},
    year = {2014},
    volume = {59},
    number = {11},
    pages = {1--25},
    url = {https://www.jstatsoft.org/article/view/v059i11},
  }