1 <?xml version="1.0"?> 2 <html xmlns="http://www.w3.org/TR/REC-html40" 3 xmlns:b="urn:BooksAreUs.org:BookInfo"> 4 <head> 5 <title>Typography</title> 6 </head> 7 8 <body> 9 <p> Welcome to the world of typography! Here is a book that you may find useful.</p> 10 <b:title style="font-family: sans-serif;">Digital Typography</b:title> 11 <b:author>Donald Knuth</b:author> 12 <b:aaa>fjfjf</b:aaa> 13 </body> 14 <book b:category="research">Numerical Analysis of Partial Differential Equations</book> 15 <book category1="research">Numerical Analysis of Partial Differential Equations</book> 16 17 18 </html>