XML Schema - odkaz na definici schématu

<book isbn="0836217462"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:noNamespaceSchemaLocation="file:library.xsd"> <!--
  mezera !!! -->

<book isbn="0836217462"
  xmlns="http://example.org/ns/books/"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://example.org/ns/books/
  file:library.xsd"> <!-- mezera !!! -->