All publications issued to the public in this country usually have a CN number. This number refers to a publication registered in China and publicly distributed in China. The serial numbers of these publications are all marked with the letter CN, and people are used to calling them CN publications.
General publications are examined annually at the beginning of each year, which is conducted at the local press and publication bureau. Then, if a journal passes the annual review, it can be published normally, and the basic information of the magazine can be found in the local press and publication bureau, and naturally the CN number can also be found. If you can't find the basic information of a magazine in the local press and publication bureau, it is generally an informal magazine.