MARC21 LEADER Bibliographic Level. Use code "i" for integrating resource. Prior to the MARC update in 2003, both serials and integrating resources were assigned "s."
MARC21 006.
Prior to 2003, a 006 field was made in order to identify the resource as integrating, since the Leader Bibliographic Level only had "s" for serials. The fixed field codes for integrating resource formerly used in 006 should now be entered in 008; no 006 is made.
MARC21 008:
TYPE OF CONTINUING RESOURCE is always "l" (L) (=Updating loose-leaf)
TYPE OF ENTRY: Use 2 [Integrated Entry]
If 310 is not present, leave the FREQUENCY blank. This should be the default. If 310 is present, then use the most appropriate code.
Note that FREQUENCY code "k" (continuously updated) is intended for websites, not updating loose-leafs.