The volume number is based on the year, which is 1 volume of the year when the journal was founded. For example, if a periodical was founded in 20 14, the periodical published in 20 14 is the first volume, and the periodical published in 20 15 is the second volume.

The issue number is based on the issue cycle. For example, if the periodical is a monthly magazine, it will issue 12 issues every year. For example, the periodicals issued in March 20 15 can be sorted into the third issue of volume 2, and the fourth issue of volume 2 issued in April 20 15 is called the fourth issue of volume 2.