\begin{Schunk}
\begin{Sinput}
 url <- "http://pj.freefaculty.org/DataSets/ANES/2002/PJTEST.sasxport"
 fn <- "anes2002.sasxport"
 if(!file.exists(fn)){
      download.file(url, mode="wb", destfile="anes2002.sasxport")
  }
\end{Sinput}
\end{Schunk}
