ex2-4.xml

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE BookCatalog
[<!ELEMENT BookCatalog  (Book)*>
<!ELEMENT Book          (Title, Author, Year)>
<!ELEMENT Title         (#PCDATA)>
<!ELEMENT Author        (#PCDATA)>
<!ELEMENT Year          (#PCDATA)>
]>
<my:BookCatalog xmlns:my="http:cswin.skuniv.ac.kr">
    <my:Book>
        <my:Title>new ideas from dead economists</my:Title>
        <my:Author>Todd G. Buchholz</my:Author>
        <my:Year>2007</my:Year>
    </my:Book>
    <my:Book>
        <my:Title>Pensées</my:Title>
        <my:Author>Blaise Pascal</my:Author>
        <my:Year>1670</my:Year>
    </my:Book>
    <my:Book>
        <my:Title>Zero to One</my:Title>
        <my:Author>Peter Thiel</my:Author>
        <my:Year>2014</my:Year>
    </my:Book>
    <my:Book>
        <my:Title>Gang Leader for a Day</my:Title>
        <my:Author>Sudhir Venkatesh</my:Author>
        <my:Year>2008</my:Year>
    </my:Book>
</my:BookCatalog>