To cite DBKGrad in publications use:

Angelo Mazza, Antonio Punzo (2014). DBKGrad: An R Package for Mortality Rates Graduation by Discrete Beta Kernel Techniques. Journal of Statistical Software, Code Snippets, 57(2), 1-18. URL http://www.jstatsoft.org/v57/c02/.

Corresponding BibTeX entry:

  @Article{,
    title = {{DBKGrad}: An {R} Package for Mortality Rates Graduation
      by Discrete Beta Kernel Techniques},
    author = {Angelo Mazza and Antonio Punzo},
    journal = {Journal of Statistical Software, Code Snippets},
    year = {2014},
    volume = {57},
    number = {2},
    pages = {1--18},
    url = {http://www.jstatsoft.org/v57/c02/},
  }