Why [J] stands for serial magazine; [M] stands for books and documents; [Z] stands for other words. What's the initials of? j,m,z? I want to know.

1. Common document types are identified by a single letter, as follows:

(1) journal [J] (journal)

(2) Monograph [M]

(3) Paper collection [c]

(4) Paper [D]

(5) patent [P] (patent)

(6) Technical standards (standardization)

Newspapers (articles)

(8) Science and Technology Report [R] (Report)

2. The type of electronic document carrier is identified by two letters, as follows:

(1) magnetic tape [MT] (magnetic tape)

(2) Disk [DK] (Disk)

(3) CD

(4) Online network [OL] (online)

The reference type identification method of electronic document carrier type is [document type identification/carrier type identification]. For example:

(1) online online database [DB/OL] (database online)

(2) Tape Database (Tape Database)

(3) CD monograph

(4) Disk software [CP/DK] (computer program on disk)

(5) Online log [J/OL] (serial online)

(6) Online bulletin board system [EB/OL]

3. Literature precipitated in monographs and papers [a];

Other unspecified literature types [Z].