# Compress references (elsarticle/natbib)

I am writing a journal article for Elsevier. I am finishing it, but I have noted that the references appear not compressed.

For example, in my article the references appear as the following

...[1], [2], [3]

...[1–3]

Could anyone help me to fix it?

I am working with the following preamble

\documentclass[preprint,12pt]{elsarticle}
% !TeX spellcheck = en_US
\usepackage{siunitx}
\sisetup{detect-weight, detect-display-math}
\sisetup{detect-inline-weight=math}
\sisetup{mode=text,per-mode=symbol}
\usepackage{booktabs}
\usepackage{graphicx}
\usepackage{pgfplots}
\usepackage{pdflscape}
\usetikzlibrary{plotmarks}
\usetikzlibrary{arrows.meta}
\usepgfplotslibrary{patchplots}
\newlength\fwidth
\setlength{\fwidth}{0.8\textwidth}
\pgfplotsset{plot coordinates/math parser=false}
\usepackage{overpic}
\pgfplotsset{compat=1.15}
\usepackage{float}
\usepackage{etoolbox}
\usepackage{bicaption}
\usepackage{makecell}
\usepackage[skip=1ex, labelfont=bf]{caption}
\usepackage[skip=0.333\baselineskip]{caption}
\usepackage{tabularx}
\newcolumntype{C}{>{\centering\arraybackslash}X}
\def\UrlFont{\normalfont}
\sisetup{per-mode=symbol}
\usepackage[margin=2.5cm]{geometry}
\usepackage[skip=0.333\baselineskip]{caption}
\usepackage{amssymb,amsmath}
\usepackage{url}
\usepackage{hyperref}
\bibliographystyle{unsrt}
\journal{Fuel}

\begin{document}

\begin{frontmatter}

\end{frontmatter}

\cite{jiang2007new,jiang2007progress,hotta2005experience}

\section*{References}

\bibliography{bilbiography}

\end{document}

\endinput


Please use the following citations as bibliography.bib:

@article{hotta2005experience,
title={EXPERIENCE OF ESTONIAN OIL SHALE COMBUSTION BASED ON CFB TECHNOLOGY AT NARVA POWER PLANTS.},
author={Hotta, A and Parkkonen, R and Hiltunen, M and Arro, H and Loosaar, J and Parve, T and Pihu, T and Prikk, A and Tiikma, T},
journal={Oil shale},
volume={22},
number={4},
year={2005}
}

@article{uibu2009co2,
title={CO2 mineral sequestration in oil-shale wastes from Estonian power production},
author={Uibu, Mai and Uus, Mati and Kuusik, Rein},
journal={Journal of environmental management},
volume={90},
number={2},
pages={1253--1260},
year={2009},
publisher={Elsevier}
}
@article{jiang2007new,
title={New technology for the comprehensive utilization of Chinese oil shale resources},
author={Jiang, XM and Han, XX and Cui, ZG},
journal={Energy},
volume={32},
number={5},
pages={772--777},
year={2007},
publisher={Elsevier}
}

@article{jiang2007progress,
title={Progress and recent utilization trends in combustion of Chinese oil shale},
author={Jiang, XM and Han, XX and Cui, ZG},
journal={Progress in Energy and Combustion Science},
volume={33},
number={6},
pages={552--579},
year={2007},
publisher={Elsevier}
}


Assuming that you are already using \cite{a,b,c}, you can accomplish this by adding the following to your preamble:

\biboptions{sort&compress}


You can see this in an example I have created on Overleaf.

To quote from the elsarticle manual:

If you want to add extra options of natbib.sty, you may use the options as comma delimited strings as arguments to \biboptionscommand.

[...]

sort&compress sorts and compresses the numbered citations. For example, citation [1,2,3] will become [1–3]

You might therefor achieve the desied result, by including the following line in your preamble:

\biboptions{sort&compress}