The "paper identification code" is used to identify the nature and type of the document and is recorded at the front of the paper. Under the abstract and keywords, there are A (theoretical and applied research papers) and B (practical technical achievements report, etc. ), c (technical management of business guidance), d (general dynamic information), e (documentation).
"Document type label" is recorded in the reference item, indicating the type of reference, marked with [], including M (book), J (journal), D (paper), S (standard), P (patent), N (newspaper), C (meeting minutes), R (report) and electronic bulletin (EB). Electronic resources as reference materials should also be marked with carrier types (OL- online network, MT- tape, DK- disk, CD- CD). For example, online electronic announcements should be marked with [EB/OL].