4xx (link) field

If you have recorded a pre-AACR2 LC heading (not MLC) in a 670 "LC in RLIN" field, and the LC heading does not match the AACR2 heading in the 1xx field on your worksheet, then examine the LC heading to determine if it would be acceptable as an AACR2 reference.

• If yes, then make the reference, and include subfield w as follows:
  4xx ‡wnna‡aLC heading
• If no, then do not make the reference, but, if possible, make an equivalent AACR2 reference, without using subfield w.