This listing contains a summary of all fields included in the MARC 21 bibliographic formats. Only fields in regular type are included in the MARC 21 LITE Bibliographic Format. Fields displayed in a smaller font are valid in a MARC 21 bibliographic record, but are not considered critical to MARC LITE records. The MARC LITE fields are linked to their field descriptions in this document. The other fields, included here for reference, are linked to the descriptions in the full MARC 21 Concise Bibliographic Format documentation.