\section{Appendix one title}\label{app1}

\begin{quote}
Says what this appendix is about, for instance further info on the web.
\end{quote}

\section{further info}

\subsection{about this subject}

\begin{itemize}
\item
  \href{http://useful.org}{}: about this and that.
\item
  \href{http://related.org}{}: about other related stuff.
\item
  \href{http://other.org}{}: more stuff.
\end{itemize}

\subsection{about other subject}

\begin{itemize}
\item
  \href{http://useful2.org}{}: about this and that.
\item
  \href{http://related2.org}{}: about other related stuff.
\item
  \href{http://other2.org}{}: more stuff.
\end{itemize}