This specifies the DSA which holds a copy of a directory
 entry subordinate to the current entry. There is no default
 value.

 Syntax:

 ADD DSA SUBORDINATE REFERENCE <name> COPY ACCESS POINT {<value>,...}

 REMOVE DSA SUBORDINATE REFERENCE <name> COPY ACCESS POINT {<value>,...}

 SET DSA SUBORDINATE REFERENCE <name> COPY ACCESS POINT {<value>,...}

 SHOW DSA SUBORDINATE REFERENCE <name> COPY ACCESS POINT

 where <value> is the access point of a DSA to which the
 Subordinate Reference refers, and is specified as follows:

    [ae title  = "<distinguished name of DSA>",
      presentation address = '<presentation address>']

 The AE Title and the presentation address are both mandatory.
 Note that the order of the AE Title and presentation
 address must be the same as that shown above.

 Specify all valid NSAPs for a DSA in an access point. This
 improves the network efficiency of the DSA, ensuring that if
 a connection to the relevant DSA already exists, it is always
 re-used.

 Refer to DSA Common_Datatypes for more information
 on how to specify an AE Title and a Presentation Address.