\begin{Schunk}
\begin{Sinput}
 library(pscl)
 myNB1<- glm.nb(undercount ~ rural + perAA + equip, data = gavote)
 ##These fail
 ##myZip1 <- zeroinfl(undercount ~ rural + perAA + equip | ., data = gavote, dist = "negbin", EM = TRUE)
 ## Succeeds
 myZip1 <- zeroinfl(undercount ~ rural + perAA + equip | 1, data = gavote, dist = "negbin", EM = TRUE)
 library(foreign)
 stdir <- "../Stata/"
 if(!file.exists(stdir)) dir.create(stdir)
 write.dta(gavote, file = paste0(stdir, "gavote.dta7"))
\end{Sinput}
\end{Schunk}
