Locator-type element

<!ELEMENT person EMPTY>
<!ATTLIST person
  xlink:type      (locator)       #FIXED "locator"
  xlink:href      CDATA           #REQUIRED
  xlink:role      CDATA           #IMPLIED
  xlink:title     CDATA           #IMPLIED
  xlink:label     NMTOKEN         #IMPLIED>
                
<!ELEMENT course EMPTY>
<!ATTLIST course
  xlink:type      (locator)       #FIXED "locator"
  xlink:href      CDATA           #REQUIRED
  xlink:role      CDATA           #FIXED "http://www.example.com/linkprops/course"
  xlink:title     CDATA           #IMPLIED
  xlink:label     NMTOKEN         #IMPLIED>

<person xlink:href="students/patjones62.xml"
        xlink:label="student62"
        xlink:role="http://www.example.com/linkprops/student"
        xlink:title="Pat Jones" />
<person xlink:href="profs/jaysmith7.xml"
	xlink:label="prof7"
	xlink:role="http://www.example.com/linkprops/professor"
	xlink:title="Dr. Jay Smith" />
<course xlink:href="courses/cs101.xml"
	xlink:label="CS-101"
	xlink:title="Computer Science 101" />