Look here for information about REFER symbolic FRU.

If the first four characters of the SRC are 3995, consult the All 3995 Publications and Documentation Web site at http://snjlnt02.sanjose.ibm.com/tape/tapetec.nsf/pages/3995pub. If the first four characters of the SRC are 3996, consult the 3996 Maintenance Information shipped with the 3996 Optical Library.