% John David Stone
% Department of Mathematics and Computer Science
% Grinnell College
% stone@cs.grinnell.edu

% created June 19, 2002
% last revised June 19, 2002

\documentclass[11pt]{article}

\begin{document}
Two main types of external entity are recognized by SGML:
\begin{enumerate}
\item entities that are specific to the system preparing/transmitting the
document, and
\item publicly declared entities whose purpose is known to more than one
system.
\end{enumerate}

Each of these main types can be further subdivided into:
\begin{itemize}
\item SGML subdocument entities,
\item SGML text entities, and
\item data entities containing text or non-SGML data not marked up using
SGML tags.
\end{itemize}
\end{document}