\documentclass[11pt,oneside]{book}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\title{Per-chapter bibliographies with chapterbib}
\usepackage[a4paper]{geometry}
\usepackage[sectionbib]{natbib}
\usepackage{chapterbib}
%%% Uncomment if you change the bibliography heading/title
% \renewcommand{\bibname}{References}
%%% Uncomment if you want to include the bibliographies at the end of each chapter in the table of contents.
% \usepackage[nottoc]{tocbibind}
\begin{document}
\frontmatter
\chapter*{Abstract}
This is \emph{not} a full thesis template! It only demonstrates how to create per-chapter references using the \texttt{chapterbib} package with BibTeX. (Do not use with BibLaTeX!)
Each chapter must be in its own \texttt{.tex} file and \texttt{include}-d into the main \texttt{.tex} file. If compiling on your own machine, run \texttt{bibtex} on \emph{each} generated \texttt{.aux} file, before running \texttt{pdflatex} twice more. (These are done automatically on Overleaf.)
\tableofcontents
\mainmatter
\include{chap1}
\include{chap2}
\backmatter
%% A list of publications can be created using this approach
\include{ownpubs}
\end{document}
