我正在引用一份旧文件，并希望正确引用。任何帮助都将不胜感激！
编辑：这是我需要采用适当格式的文档部分。
%----------------------------------------------------------------------
% Number
%----------------------------------------------------------------------
\documentclass[psamsfonts]{amsart}
\usepackage{amssymb, amsrefs, graphicx, float, centernot, amsmath, tabu, caption, booktabs}
\usepackage[english]{babel}
\usepackage [autostyle, english = american]{csquotes}
\graphicspath{ {./images/} }
\MakeOuterQuote{"}
\raggedbottom
\newtheorem{axiom}{Axiom}[section]
\newtheorem{definition}{Definition}[section]
\newtheorem{lemma}{Lemma}[section]
\newtheorem{theorem}{Theorem}[section]
\newtheorem{corollary}{Corollary}[theorem]
\newtheorem*{example}{Ex}
\newtheorem*{postulate}{Postulate}
\newtheorem*{proposition}{Proposition}
\theoremstyle{remark}
\newtheorem*{remark}{Remark}
\theoremstyle{acknowledgements}
\theoremstyle{addendum}
\newtheorem*{addendum}{The cardinal numbers $\mathfrak{p}$ and $\mathfrak{t}$}
\newtheorem*{acknowledgements}{Acknowledgements}
\numberwithin{equation}{section}
\newtheorem{exercise}{Exercise}
\newtheorem{solution}{Solution}
\begin{document}
\section*{Chapter 0}
"After the definitions we have given of \emph{nothing} and
\emph{infinity}, the following rules taken from the writings of an
eminent mathematician, it is prefumed, will not be thought
prepofterous; and in the higher branches of the mathematics they
will be found of confiderable utility to ftudents"
- \emph{Jared Mansfield, 1802 speaking to Emerson's Algebra}
\subsection{Emerson's Algebra}
\begin{enumerate}
\item If \emph{nothing} multiply any finite quantity, the product will be nothing.
\item If \emph{nothing} multiply an infinite quantity, the product is a finite quantity. Or a finite quantity is a mean proportional between nothing and infinity.
\item If a finite quantity be divided by nothing, the quotient is infinite,
\item If nothing be divided by nothing, the quotient is a finite quantity.
\item If a quantity be nothing and the index of its power nothing, that quantity is equal to unity ; or the infinitely fmall power of an infinitely fmall quantity is infinitley near 1.
\item Adding or fubtracting any finite quantities to or from an infinite quantity, makes no alteration, therefore,
\item In any equation where are fome quantities infinitely lefs than others ; they may be thrown out of the equation.
\item An infinite quantity may be confidered either as affirmative or negative.
\end{enumerate}
\end{document}
答案1
这不是 ft 连字符，而是长-t 连字。另一个是 ct 连字。并非每种字体都包含此类符号，通常您必须使用 OpenType 之类的系统（通过 XeLaTeX 或 LuaLaTeX）来访问它们。以下是使用 Libertinus 字体的示例：
\documentclass{article}
\usepackage{fontspec}
\setmainfont{libertinusserif-regular.otf}[Ligatures=Historic]
\begin{document}
ſtudents
products
\end{document}
结果：
需要激活诸如 ct 连字符之类的东西是很常见的Ligatures=Historic，但您必须查看字体的文档以了解哪种字体合适。至于在较长的文本中使用这种样式，您必须首先做出决定：是否应该对“普通”文本和历史引文使用具有不同功能的相同字体，还是应该使用不同的字体？下面是使用相同字体的简单示例：
\documentclass[psamsfonts]{amsart}
\usepackage{amssymb, amsrefs, graphicx, float, centernot, amsmath, tabu, caption, booktabs}
\usepackage[english]{babel}
\usepackage [autostyle, english = american]{csquotes}
\usepackage{libertinus}
\newcommand{\histligs}{\addfontfeatures{Ligatures=Historic}}
\begin{document}
{\histligs product ſtudent preſumed \textit{is different} from prefumed}
Some normal text with product and a formula
\begin{equation}
E = mc^2
\end{equation}
\end{document}
结果：
我再次使用 Libertinus，因为它不仅支持必要的文本功能，还支持数学。如果你想让历史引文脱颖而出，你可以像这样切换字体：
\documentclass[psamsfonts]{amsart}
\usepackage{amssymb, amsrefs, graphicx, float, centernot, amsmath, tabu, caption, booktabs}
\usepackage[english]{babel}
\usepackage [autostyle, english = american]{csquotes}
\usepackage{fontspec}
\newfontfamily{\histligs}{libertinusserif-regular.otf}[%
Ligatures = Historic,
ItalicFont = libertinusserif-italic.otf]
\begin{document}
{\histligs product ſtudent preſumed \textit{is different} from prefumed}
Some normal text with product and a formula
\begin{equation}
E = mc^2
\end{equation}
\end{document}
结果：
当然，除了 Latin Modern 和 Libertinus 之外，还有更多令人愉悦的字体组合，但找到这些字体组合绝非易事。
请注意，所有这些文档都必须使用支持 OpenType 的 TeX 引擎（XeTeX 或 LuaTeX）进行处理。