+<sect>The Input (Data) File Format
+
+<p>
+The retrieval module is designed to manage data derived from a
+variety of different input sources. When used on the client side, the
+source format may be GRS-1 ISO2709. On the server side, the source may
+be a structured ASCII file, augmented by a set of patterns that
+describe the structure of the document.
+
+What we think of as the native source format - the one that is
+guaranteed to provide complete access to the facilities of the module,
+is an &dquot;SGML-like&dquot; syntax, based on an inferred DTD, which
+is in turn based on the profile information from the various files
+mentioned in this document.
+
+Like SGML, an input record consists of tags and data. The tags are
+enclosed by brackets (<...>). As a general rule, each tag should
+be matched by a corresponding close tag, identified by the same tag
+name preceded by a slash (/).
+