To cite betareg in publications use:

Cribari-Neto F, Zeileis A (2010). “Beta Regression in R.” Journal of Statistical Software, 34(2), 1–24. doi:10.18637/jss.v034.i02.

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

Grün B, Kosmidis I, Zeileis A (2012). “Extended Beta Regression in R: Shaken, Stirred, Mixed, and Partitioned.” Journal of Statistical Software, 48(11), 1–25. doi:10.18637/jss.v048.i11.

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},
    doi = {10.18637/jss.v034.i02},
  }

  @Article{,
    title = {Extended Beta Regression in {R}: Shaken, Stirred, Mixed,
      and Partitioned},
    author = {Bettina Gr\"un and Ioannis Kosmidis and Achim Zeileis},
    journal = {Journal of Statistical Software},
    year = {2012},
    volume = {48},
    number = {11},
    pages = {1--25},
    doi = {10.18637/jss.v048.i11},
  }