我查看了各种相关答案，但我对 Natbib 还不熟悉，无法找出问题所在，希望您能帮忙。以下是 tex 代码：
\documentclass{article}
% for 2-column layout use \documentclass[USenglish,twocolumn]{article}
\usepackage[utf8]{inputenc} %(only for the pdftex engine)
%\RequirePackage[no-math]{fontspec}[2017/03/31]%(only for the luatex or the xetex engine)
\usepackage[big,online]{dgruyter} %values: small,big | online,print,work
\usepackage{lmodern}
\usepackage{microtype}
\usepackage{amssymb,amsmath,amsgen,theorem,graphicx,epsfig}
\usepackage[numbers,square,sort&compress]{natbib}
\usepackage{booktabs, multirow}
%\usepackage{cleveref}
\usepackage{subcaption}
\usepackage{caption}
% New theorem-like environments will be introduced by using the commands \theoremstyle and \newtheorem.
% Please note that the environments proof and definition are already defined within dgryuter.sty.
\begin{document}
Power system oscillations’ behavior is a dominant thought in the power system stability discipline\cite{Pérez-Londoño:2012,Muñoz:2011}.
\begin{thebibliography}{99}
\bibitem{Pérez-Londoño:2012}
\href{https://ieeexplore.ieee.org/document/6319119}{S. Pérez-Londoño, L. Rodríguez-García, Y. U. López. Effects of doubly fed wind generators on voltage stability of power systems. In \emph{2012 Sixth IEEE/PES Transmission and Distribution: Latin America Conference and Exposition (T{\&}D-LA)}; 2012; Montevideo, Uruguay: pp. 1-6. doi: 10.1109/TDC-LA.2012.6319119}
\bibitem{Muñoz:2011}
\href{https://ieeexplore.ieee.org/document/5772545}{J. C. Muñoz, C. A. Cañizares. Comparative stability analysis of DFIG-based wind farms and conventional synchronous generators. In \emph{2011 IEEE/PES Power Systems Conference and Exposition, PSCE} 2011; Phoenix, AZ, USA: pp. 1-7. doi: 10.1109/PSCE.2011.5772545}
\end{thebibliography}
\end{document}
答案1
错误消息已经说明了这一点——您不能在引文中使用非 ASCII 字符，如 öäüñ 等。这些字符不在 ASCII 表中，只能在其他更广泛的表中找到，如 UTF-8 或 UTF-16。
将“ñ”的使用重构为简单的“n”应该可以解决您的问题。可能不需要重构引文的内容，而只需重构引文标签（即\bibitem{Muñoz:2011}重构为\bibitem{Munoz:2011}）。