The meaning of letters in the paper.

According to GB3469-83 "Document Types and Document Carrier Codes", it is identified by a single letter: m- monograph (including works on history and chronology in ancient books); C- prose collection; N- newspaper articles; Journal articles; D- thesis; R- research report; S standard; Patents; A-precipitation documents in monographs and papers; Z—— Other unspecified literature types. The type of electronic document is identified by two letters: DB-Database; Computer program; Electronic bulletin. For electronic documents with non-paper carriers, the carrier type is indicated in the reference identification: DB/OL- online database; Db/mt- tape database; M/CD-CD books; CP/DK- disk software; J/ol- online journal; Online electronic bulletin.