To cite COZIGAM in publications use:

Hai Liu, Kung-Sik Chan (2010). Introducing COZIGAM: An R Package for Unconstrained and Constrained Zero-Inflated Generalized Additive Model Analysis. Journal of Statistical Software, 35(11), 1-26. URL http://www.jstatsoft.org/v35/i11/.

Corresponding BibTeX entry:

  @Article{,
    title = {Introducing {COZIGAM}: An {R} Package for Unconstrained
      and Constrained Zero-Inflated Generalized Additive Model
      Analysis},
    author = {Hai Liu and Kung-Sik Chan},
    journal = {Journal of Statistical Software},
    year = {2010},
    volume = {35},
    number = {11},
    pages = {1--26},
    url = {http://www.jstatsoft.org/v35/i11/},
  }