As Ive already written, getting data into R from your precious xlsx files is really handy. No need to clutter up your computer with txt or csv files. The previous post I wrote about the gdata package for importing data from xlsx files and was pointed to, among others, the xlsx package. xlsx seems to 









Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).