在 blockquote 中使用部分类型

Question

我对乳胶还不熟悉，但有人可以向我解释一下为什么这个有效：

\begin{document}
\begin{quote}
\subsubsection{Just some Text}
\end{quote}
\end{document}

但这一个没有：

\begin{document}
\begin{quote}
\paragraph{Just some Text}
\end{quote}
\end{document}

第二个示例导致以下错误：

! LaTeX Error: Something's wrong--perhaps a missing \item.

完整文件如下：

\documentclass[]{article}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage{amssymb,amsmath}
\usepackage{ifxetex,ifluatex}
\usepackage{fixltx2e} % provides \textsubscript
% use upquote if available, for straight quotes in verbatim environments
\IfFileExists{upquote.sty}{\usepackage{upquote}}{}
\ifnum 0\ifxetex 1\fi\ifluatex 1\fi=0 % if pdftex
  \usepackage[utf8]{inputenc}
\else % if luatex or xelatex
  \usepackage{fontspec}
  \ifxetex
    \usepackage{xltxtra,xunicode}
  \fi
  \defaultfontfeatures{Mapping=tex-text,Scale=MatchLowercase}
  \newcommand{\euro}{€}
\fi
% use microtype if available
\IfFileExists{microtype.sty}{\usepackage{microtype}}{}
\ifxetex
  \usepackage[setpagesize=false, % page size defined by xetex
              unicode=false, % unicode breaks when used with xetex
              xetex]{hyperref}
\else
  \usepackage[unicode=true]{hyperref}
\fi
\hypersetup{breaklinks=true,
            bookmarks=true,
            pdfauthor={},
            pdftitle={},
            colorlinks=true,
            urlcolor=blue,
            linkcolor=magenta,
            pdfborder={0 0 0}}
\urlstyle{same}  % don't use monospace font for urls
\setlength{\parindent}{0pt}
\setlength{\parskip}{6pt plus 2pt minus 1pt}
\setlength{\emergencystretch}{3em}  % prevent overfull lines
\setcounter{secnumdepth}{0}

\author{}
\date{}

\begin{document}
\begin{quote}
\subsubsection{Just some Textj}
\end{quote}
\end{document}

- - 编辑 - -

如果其他人正在寻找解决方案，我在前言中添加了以下内容，似乎有效。如果有更好的方法，请提出来。

% added to fix paragraphs and subparagraphs
\makeatletter
    \renewcommand\paragraph{%
        \@startsection{paragraph}{4}{0mm}%
            {-\baselineskip}%
            {.3\baselineskip}%
            {\normalfont\normalsize\bfseries}}
    \renewcommand\subparagraph{%
        \@startsection{subparagraph}{5}{0mm}%
            {-\baselineskip}%
            {.3\baselineskip}%
            {\normalfont\normalsize\bfseries}}
\makeatother