我的纯乳胶demo.tex如下：

\documentclass{article}

\usepackage[hidelinks]{hyperref}
\usepackage[numbers,super,square,sort&compress]{natbib}

\begin{document}

statistics \cite{anderson2003introduction,efron2004least,hastie2009elements}

\bibliographystyle{unsrtnat}
\nocite{*}
\bibliography{ref}
\addcontentsline{toc}{section}{References}

\end{document}

它运行良好，其中ref.bib包含

@Book{anderson2003introduction,
  author    = {Anderson, Theodore Wilbur},
  publisher = {Wiley},
  title     = {An introduction to multivariate statistical analysis},
  year      = {2003},
  address   = {New Jersey},
  edition   = {3},
}
@Article{efron2004least,
  author    = {Efron, Bradley and Hastie, Trevor and Johnstone, Iain and Tibshirani, Robert},
  title     = {Least angle regression},
  journal   = {The Annals of Statistics},
  year      = {2004},
  volume    = {32},
  number    = {2},
  pages     = {407--499},
}
@Book{hastie2009elements,
  author    = {Hastie, Trevor and Tibshirani, Robert and Friedman, Jerome},
  publisher = {Springer},
  title     = {The elements of statistical learning: {Data} mining, inference, and prediction},
  year      = {2009},
  address   = {New York},
  edition   = {2},
}
@Book{fan2020statistical,
  author    = {Fan, Jianqing and Li, Runze and Zhang, Cun-Hui and Zou, Hui},
  publisher = {CRC},
  title     = {Statistical foundations of data science},
  year      = {2020},
  address   = {Boca Raton},
}

我想将demo.tex转换为rmarkdown文件tex2rmd.rmd，并尝试

---
output: 
  pdf_document:
    keep_tex: yes
    citation_package: natbib
natbiboptions: "numbers,super,square,sort&compress"
# natbiboptions: "numbers,super,square" #test
biblio-style: unsrtnat
nocite: '@*'
bibliography: ref.bib
link-citations: yes
colorlinks: no
---

statistics [@anderson2003introduction; @efron2004least; @hastie2009elements]

# References

这会产生如下错误

! Missing \endcsname inserted.
<to be read again> 
                   \&
l.351 \newcommand
                 \NAT@aysep{,} \newcommand\NAT@yrsep{,}

然后，我从keep_tex: yes功能检查tex2rmd.tex文件，发现问题发生在

\usepackage[numbers,super,square,sort\&compress]{natbib}

其中存在sort\&compress而不是sort&compress。如何修复此问题？
此外，我使用natbiboptions: "numbers,super,square"代替测试目的，发现nocite: '@*'也不工作（它应该显示所有4项，而不是引用的3项）。我忽略了什么吗？