在文档类 elsarticle 中，双列为什么参考编号在 pdf 中不可见但在单列中可见？

Question

我正在使用类 elsarticle double col 如下

\documentclass[final, 5p, times, authoryear, twocolumn]{elsarticle}
\begin{document}
\bibliographystyle{abbrvnat} % (For authoryear Elsevier citations)

% The bibliography file

\bibliography{ref_els}


\end{document}

那么参考编号不可见，但是当我使用单列作为

\documentclass[times]{elsarticle}

    
the reference number are visible, why so?

数字也是按顺序排列的，就像 jebref 中通常发生的那样。请指导我哪里错了。

问候

Answer 1

完成后就会出现数字bibtex + pdflatex + pdflatex。

使用\bibliographystyle{abbrvnat}

% !TeX TS-program = pdflatex

\documentclass[final,5p,times,twocolumn]{elsarticle}    

\begin{filecontents}{mainrefs.bib}
    @article{einstein,
        author="Albert Einstein",
        title="{Zur Elektrodynamik bewegter Korper}",
        journal="Annalen der Physik",
        volume="322",
        number="10",
        pages="891--921",
        year="1905",
        DOI ="http://dx.doi.org/10.1002/andp.19053221004",
        keywords="physics"
    }
    
    @book{dirac,
        title={The Principles of Quantum Mechanics},
        author={Paul Adrien Maurice Dirac},
        isbn={9780198520115},
        series={International series of monographs on physics},
        year={1981},
        publisher={Clarendon Press},
        keywords = {physics}
    }
\end{filecontents}

\usepackage{kantlipsum}

\journal{Nuclear Physics B}

\begin{document}

\begin{frontmatter}

\title{}

\author{}

\begin{abstract}
Let us suppose that the noumena have nothing to do
with necessity, since knowledge of the Categories is a posteriori.
\end{abstract}

\begin{keyword}
Space \sep  Time
\end{keyword}

\end{frontmatter}

\section{Introduction}

The history starts with \cite{einstein} and continues with   \cite{dirac}.
 
\kant[1-3]

\bibliographystyle{abbrvnat}

%\bibliographystyle{elsarticle-num}% ordered numbers <<<<<<

\bibliography{mainrefs}

\end{document}

或者改用\bibliographystyle{elsarticle-num}有序数字。