According to the literature type and the literature carrier code, the types of works represented by M, J and C are

M: Monographs (including works on history and chronicles in ancient books). M is the abbreviation of the English word "monograph", which means monograph.

This kind of works, such as "Rabbit Raising in China".

J: Journal articles. J is the abbreviation of the English word "journal", which means: daily newspaper, journal, diary; Periodicals, periodicals, magazines.

C: Essays. C is the abbreviation of the English word "symposium". Symposium means: seminar, academic report.

A work represented by letters.

M: Monographs (including works on history and chronicles in ancient books)

C: thesis

N: newspaper articles

Journal articles

doctoral dissertation

R: research report

Student: standard

patent

A: Literature precipitated in monographs and papers.

Z: Other unspecified literary types.

Electronic document types are identified by two letters:

database

computer program

EB: electronic bulletin

For electronic documents with non-paper carriers, the carrier type shall be indicated in the reference mark:

DB/OL: Database on Online Network

DB/MT: tape database

M/CD: CD books

CP/DK: Disk Software

J/OL: online journal

EB/OL: online electronic bulletin

References:

Web page link (Baidu Library: document type and document carrier code).