在 natbib 中插入逗号分隔的引用参考

Question

我试图在 natbib 中使用方括号进行引用，其中以逗号分隔作者和年份，如下所示：

[Einstein, 1905]

在文本中我成功做到了：

\usepackage{natbib}
\bibliographystyle{dinat}
\setcitestyle{authoryear,open={[},close={]}}

但是当使用 \bibliography{sample} 打印参考文献时，作者和年份之间没有逗号。我在 macOS High Sierra 上使用 XeLaTex 和 BibTex 编译文档。

示例.tex：

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[english]{babel}

\usepackage{natbib}
\bibliographystyle{dinat}
\setcitestyle{authoryear,open={[},close={]}}

\title{Bibliography management: \texttt{natbib} package}
\author{Share\LaTeX}
\date { }

\begin{document}

\maketitle

This document is an example of \texttt{natbib} package using in bibliography
management. Three items are cited: \textit{The \LaTeX\ Companion} book 
\citep{latexcompanion}, the Einstein journal paper \citep{einstein}, and the 
Donald Knuth's website \citep{knuthwebsite}. The \LaTeX\ related items are 
\citep{latexcompanion,knuthwebsite}. 

\medskip

\bibliography{sample}

\end{document}

示例.bib：

@article{einstein,
    author =       "Albert Einstein",
    title =        "{Zur Elektrodynamik bewegter K{\"o}rper}. ({German})
        [{On} the electrodynamics of moving bodies]",
    journal =      "Annalen der Physik",
    volume =       "322",
    number =       "10",
    pages =        "891--921",
    year =         "1905",
    DOI =          "http://dx.doi.org/10.1002/andp.19053221004"
}

@book{latexcompanion,
    author    = "Michel Goossens and Frank Mittelbach and Alexander Samarin",
    title     = "The \LaTeX\ Companion",
    year      = "1993",
    publisher = "Addison-Wesley",
    address   = "Reading, Massachusetts"
}

@misc{knuthwebsite,
    author    = "Donald Knuth",
    year = 2019,
    title     = "Knuth: Computers and Typesetting",
    url       = "http://www-cs-faculty.stanford.edu/\~{}uno/abcde.html"
}

要想在作者和年份之间添加逗号，必须怎么做？

编辑：

示例取自分享乳胶。