Which letter stands for dissertation?

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

Monograph m; Newspapers; Journal j; Patent document p; Compilation g; Ancient books o; Technical standards.

Dissertation d; Science and technology report r; Reference tool k; Search tool w; File b; Tape a.

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

Related information introduction:

Dissertations can be divided into bachelor's dissertations, master's dissertations and doctoral dissertations according to the degree applied.

According to different research methods, dissertations can be divided into three categories: theoretical, experimental and descriptive. The research methods used in theoretical degree thesis are theoretical proof, theoretical analysis and mathematical reasoning, and scientific research results are obtained through these research methods.

The experimental paper uses experimental methods to carry out experimental research and obtain scientific research results; Descriptive papers use the methods of description, comparison and explanation to study newly discovered things or phenomena and obtain scientific research results.