\documentclass[a4paper,11pt]{article}

\usepackage{parskip}    %% Because I like un-indented text with white space 
                        %% between paragraphs

\usepackage{natbib}     %% Highly recommended!  Provides \citep and \citet

\usepackage[margin=1in]{geometry}

\usepackage{hyperref}   %% To make hyperlinks in the output document

\begin{document}

\title{Use \texttt{natbib} package, with \texttt{chicago} bibliography style}
\author{David Firth}
\date{}

\maketitle
\thispagestyle{empty}

\section{The source files for this document}

Please study the \LaTeX\ file \texttt{mydoc.tex} and the references in 
\texttt{myrefs.bib}, to see how this document was made.  The (standard) 
processing sequence is 
\texttt{latex}, \texttt{bibtex}, \texttt{latex}, \texttt{latex}.

\section{A sample of text with two different types of citation}

The Plackett-Luce model \citep{plackett:1975,luce:1977} is amenable to Bayesian 
analysis, as shown in \citet{guiver+snelson:2009}.

\section{The \LaTeX\ code to be used for those two types of citation}

Note the use of \texttt{natbib}'s two basic citation commands \texttt{citet} 
and \texttt{citep}, as in 
\begin{verbatim}
  \citet{guiver+snelson:2009}
\end{verbatim}
for citations that are part the text, and 
\begin{verbatim}
   \citep{plackett:1975,luce:1977}
\end{verbatim}
for citations in parentheses.

For other possibilities, see for example the \texttt{natbib} reference 
sheet at \url{http://merkel.texture.rocks/Latex/natbib.php?lang=en}.

\bibliographystyle{chicago}
\bibliography{myrefs}

\end{document}
