There are many other interesting papers and topics on the archaeology of Precolumbian Mesoamerican Indians at Dr. Porter's Maya Glyphs site. Museo del Americas, Madrid Amatl paper screenfold painted on both sides. For the most recent scholarship on the Madrid Codex, check out the collection of Papers on the Madrid Codex edited by Victoria Reifler Bricker and Gabrielle Vail, with papers by Chrisopher L. von Nagy, Cassandra R. Bill, Donald H. Graff, and the editors. Several pages from the Madrid can be viewed at Troano Codex , created by Stephen Short at SMU's Central University Libraries Government Resources page. First published in 1973 in the exhibit catalog for this show called The Maya Scribe and His World , by Michael Coe.
Some scholars think the document is a fake, but most seem to share the opinion that it is genuine.
It's a little difficult to see in the graphic above, but you'll note that each page has a single column of repeating calendrical glyphs, and a maya numeral tied in a bundle. This is quite a bit different from the more complex glypic texts, read typically in paired columns, found in the other three codices. It is most like pages found in the Paris Codex. They don't attribute the source, but my guess is that it's from National Geographic . If you've found this page, there's a good chance you've already seen the Maya Epigraphic Database .