ction</a></td></tr>
 <tr><td></td><td valign="top" align="left"></td><td colspan="3" width="100%"><a href="r5rs-2.html#Background">Background</a></td></tr>
 <tr><td></td><td valign="top" align="left"></td><td colspan="3" width="100%"><a href="r5rs-2.html#Acknowledgements">Acknowledgements</a></td></tr>
 <tr><td valign="top" align="left"></td><td colspan="4" width="100%"><a href="r5rs-3.html#Table-of-contents">Table of contents</a></td></tr>
 <tr><td valign="top" align="left">1</td><td colspan="4" width="100