For linking to other pages or sites use <extref> with the attribute href="..."
(for example: use with links in repository)

Extended Reference

Description: A linking element that can include text and subelements as part of its reference to an electronic object that is external to the EAD document. For TARO, use the HREF attribute to identify the external object.

EXAMPLE:

<repository label="Repository" encodinganalog="852$a">
   <extref href="http://www.cah.utexas.edu/" show="new" actuate="onrequest">
     <corpname encodinganalog="852$a">
        <subarea>Center for American History,</subarea>
        The University of Texas at Austin
     </corpname>
   </extref>
<repository>