Minimum reproducible example:
% main.tex
\documentclass{article}
\usepackage{natbib}
\begin{document}
Example citation: \cite{loenen2014type}
\bibliographystyle{agsm}
\bibliography{reference.bib}
\end{document}
reference.bib
@article{loenen2014type,
title={Type I restriction enzymes and their relatives},
author={Loenen, Wil AM and Dryden, David TF and Raleigh, Elisabeth A and Wilson, Geoffrey G},
journal={Nucleic acids research},
volume={42},
number={1},
pages={20--44},
year={2014},
publisher={Oxford University Press}
}
Where the letter 'i' in "Type I" is not correctly capitalised. Now I know you can add an extra layer of braces to force keeping the capitalisation, but is it possible to just tell natbib to "keep it as-is"? To be fair, many BibTeX citation suppliers simply just use one layer of braces regardless of any uppercase letters in the title, and it would be much more time-consuming and error-prone if you correct every of them manually.
Also \DeclareFieldFormat{titlecase}{#1} only works for BibLaTeX.
Wonder if there's a natbib equivalent.

