To cite betareg in publications use:

If you use betareg(), please cite:

Francisco Cribari-Neto, Achim Zeileis (2010). Beta Regression in R. Journal of Statistical Software 34(2), 1-24. URL http://www.jstatsoft.org/v34/i02/.

If you use betatree(), betamix(), or bias correction/reduction in betareg(), please cite:

Bettina Gruen, Ioannis Kosmidis, Achim Zeileis (2011). Extended Beta Regression in R: Shaken, Stirred, Mixed, and Partitioned. Working Paper 2011-22. Working Papers in Economics and Statistics, Research Platform Empirical and Experimental Economics, Universitaet Innsbruck. URL http://EconPapers.RePEc.org/RePEc:inn:wpaper:2011-22

Corresponding BibTeX entries:

  @Article{,
    title = {Beta Regression in {R}},
    author = {Francisco Cribari-Neto and Achim Zeileis},
    journal = {Journal of Statistical Software},
    year = {2010},
    volume = {34},
    number = {2},
    pages = {1--24},
    url = {http://www.jstatsoft.org/v34/i02/},
  }

  @TechReport{,
    title = {Extended Beta Regression in {R}: Shaken, Stirred, Mixed,
      and Partitioned},
    author = {Bettina Gr\"un and Ioannis Kosmidis and Achim Zeileis},
    institution = {Working Papers in Economics and Statistics, Research
      Platform Empirical and Experimental Economics, Universit\"at
      Innsbruck},
    year = {2011},
    type = {Working Paper},
    number = {2011-22},
    month = {October},
    url = {http://EconPapers.RePEc.org/RePEc:inn:wpaper:2011-22},
  }