File type identification: File type identification is a symbol indicating various types of reference files. When writing a paper, references must be identified by document type. According to GB 3469-83 "File Types and File Carrier Codes", common file types are identified with single letters, and electronic files are identified with double letters. Example: 1. Commonly used literature types are identified by a single letter:

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

Essays

Newspaper articles

Journal articles

Doctoral dissertation

R- research report

S standard

patent

A—— Precipitated documents in monographs and papers.

Z—— Other unspecified literature types

Two, with two letters as the identification of electronic file type:

database

computer program

Example of e B- electronic bulletin (see Resources): 1. Liu Zhongneng, Jin. Study on the Synthesis of 4- methylimidazole [J]. Fine Chemical Industry, 2002 (2):103-105 [J] indicates that the cited literature type is-Journal 2: Jiang Tingda. Skin lightening polysaccharide [M]. Beijing: Chemical Industry Press, 200 1: 127 [M] with references.

1. The capital letters of the references published in the paper represent the meaning: /link? URL = _ ptul6Eu9pi2kmwrtpwyuk78loe3qc0hw36o25EnkZixydu4Rgiq652XII YK8byVDXDA0xy1vbuucfupi0Rkpureyhjrgn24JgQRwbi2, document type identification/link? URL = 1 C4 tbx r 2t 5 piiycc 2 SFE-D2 vduronylyf 2 x 44 qlsyivby 4 ci 5 kez 4 fenyqhxuklijhfx 7 vnaqebwnmdssbha