\documentclass{article}
\usepackage{url}
\usepackage{natbib}
\usepackage{float}
\usepackage{fancyvrb}
\usepackage{exercises}
\usepackage{nextpage}
\pagestyle{headings}
\setcounter{tocdepth}{1}
\setlength{\voffset}{-1.5cm}
\setlength{\hoffset}{-0.5cm} \setlength{\textwidth}{15.5cm}
\setlength{\textheight}{23cm}
\title{Data Analysis with R Laboratories 1 \& 2, with R Code}
\author{John Maindonald}
\begin{document}
\maketitle

\include{r-exs1}
\cleartooddpage
\setcounter{section}{0}
\include{r-exs2}
\end{document}