The same reference is cited many times with only one serial number, and the page number of each reference is placed outside the serial number of the reference in the upper corner of the text, so it is not repeated in the list of references after the text. Therefore, if you quote the same article many times in your paper, you only need to mark the serial number and page number of the article when you quote it for the first time. If you need to quote the article again, just mark the serial number and page number of the article in the text.