According to the provisions of GB3469-83 "Document Type and Document Carrier Code", it is identified by a single letter: M - monograph (including history and chronicles in ancient books) C - collection of papers N - newspaper article J——Journal article D——Dissertation R——Research report S——Standard P——Patent A——Extracted documents in monographs and collections Z——Other unspecified document types Electronic document types are identified by double letters : DB - database CP - computer program EB - electronic bulletin non-paper-based carrier electronic documents, also indicate the carrier type in the reference mark: DB/OL - online database DB/MT - tape database M /CD——Compact disc book CP/DK——Disk software J/OL——Online journal EB/OL——Online electronic bulletin 1. Reference description format 1. Journal author. Title〔J〕. Journal title, year of publication, volume (issue): starting and ending page numbers 2. Author of the monograph. Book title〔M〕. Edition (the first edition is not described). Place of publication: Publisher, Year of publication: Starting and ending page numbers 3. Author of the collection of papers. Title〔C〕． editor. Title of thesis collection, place of publication: publisher, year of publication: starting and ending page numbers 4. Author of thesis. Title〔D〕. Save location. Save the unit. Year 5, patent document title [P]. Country. Types of patent documents. Patent number. Publication date 6. Standard number. Standard name〔S〕 7. Newspaper author. Title〔N〕． Newspaper name. Publication date (edition) 8. Report author. Title〔R〕． Save location. Year 9, author of electronic documents. Title [Electronic document and carrier type identification]. Document source, date 2. Document type and identification 1. According to the provisions of GB3469, various commonly used document identifications are as follows: ①Journal〔J〕 ②Monograph〔M〕 ③Proceedings〔C〕 ④Dissertation〔D〕 ⑤Patent〔P 〕 ⑥Standard〔S〕 ⑦Newspaper〔N〕 ⑧Technical report〔R〕 2. Electronic document carrier types are identified by two letters, as follows: ①Tape [MT] ②Disk [DK] ③Compact disc [CD] ④Online network [ OL] 3. The reference type identification method for electronic document carrier types is: [Document type identification/carrier type identification]. For example: ①Online database [DB/OL] ②Tape database [DB/MT] ③Compact disc book [M] /CD〕 ④Disk software〔CP/DK〕 ⑤Online journal〔J/OL〕 ⑥Online electronic bulletin〔EB/OL〕