| 598 BB | Box barcode |
| 599 BB | System number for record overlay |
| 599 B0 | For holdings see: (barcode numbers for Title IIC 1986 project, including Div. Lib. locations |
| 599 00 | MIT thesis supervisor note |
| 599 01 | Thesis keywords |
| 599 02 | Electronic journal note |
| 599 03 | Rare collection |
| 599 04 | Receipt history record note |
| 599 05 | Cataloging note for Acquisition use |
| 599 06 | ILB number and lending library |
| 599 07 | Precat non-roman language code |
| 599 08 | Notes for Chomsky collection |
| 599 10 | Donor note |
| 599 11 | Flag to prevent pre-check SFX button from appearing on records without a URL but has false positive Text in |a: nobutton |
| 599 83 |
Cataloging treatment [currently used by Serials only to generate note in brief display, e.g. "OTHER VOLS: Cataloged separately after vol. for 1984"] |
| 901 | LC USE ONLY |
| 910 | Cataloger initials & date cataloged (yymmdd) |
| 911 | LC USE ONLY: X-COPY INFORMATION |
| 936 | OCLC defined: Dates or volume designation of last issue consulted |
| 938 | OCLC-defined field for vendor information supplied by OCLC: used to support PromptCat and Prism Selection Services |
| 949 | Holdings |
| 949 99 | Serials holdings [obsolete: usage in GLIS only; some may still exist in BARTON] |
| 98x 993 |
Defined by Yankee Book Peddlar for GOBI records |
| 994 | OCLC USE ONLYL: Holding library code and OCLC Institution symbol; code for "update", "replace" |