References in this paper refer to documents or procedural policies promulgated by the state, which should be represented by the letter S.

For example, references are national standards, and the format of Basic Rules of Chinese Pinyin Orthography is:

Gb/t16159-1996, basic rules of Chinese pinyin orthography [S].

Reference standard format refers to the publicly published document format for writing papers, which can be divided into book [m], [c] periodical press conference, newspaper article [n], [j], periodical article [d] report [r], standard [s], patent [p], [1] periodical literature and magazine [

Types of electronic documents: database [[DB]], computer [[CP]], electronic bulletin [[EB]]

Electronic literature carrier types: Internet [OL], CD [CD], magnetic tape [[MT]], magnetic disk [[DK]].

According to GB3469-83 "File Types and File Carrier Codes", reference file types and file types are identified by a single letter:

Monograph m; Newspaper n; Journal j; Patent document p; Compilation g; Ancient books o; Technical standards;

Dissertation d; Scientific and technological report; Reference tool k; Search tool w; File b; Tape a;

Chart q; Record l; Product sample x; Video tape v; Meeting minutes; Chinese translation test;

Music score I; Movie y; Manuscript h; Microfilm u; Slide z; Miniature flat film f; Other e.