1 <catalog prefer="public" xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog">

     2 

     3     <system systemId="http://www.oracle.com/sequence.dtd" uri="second.dtd"/>

     4     <system systemId="http://www.oracle.com/sequence_next.dtd" uri="second.dtd"/>

     5     <system systemId="http://www.oracle.com/sequence_second.dtd" uri="second.dtd"/>

     6 

     7 </catalog>