My problem arises from

CodePudding user response：

You could use the chem-angew style:

\documentclass{article}

\usepackage[hidelinks]{hyperref}
\usepackage[style=chem-angew,autocite=superscript]{biblatex}
\addbibresource{ref.bib}

\newcommand{\citep}[1]{\autocite{#1}}


\begin{document}

statistics \citep{anderson2003introduction,efron2004least,hastie2009elements}

\printbibliography[heading=bibliography,title=References]
\nocite{*}

\end{document}