According to APA specification, different documents of the same author can be distinguished by the year of publication, and documents published in the same year should be distinguished by adding another letter to the year (the same letter should be added to the corresponding entry in the reference description after the text), such as:

(bloom, 2003a, 2003b)?

In this article, I quoted an article/book by Bloom in 2003 and another article/book in 2003. In addition, other articles or books written by Bloom in 2003 are quoted in the later part of this paper. This is only the "first" quotation of Pop's works published in 2003.

Extended data 1, citing the literature of two authors.

If you want to quote the works of two authors, you should indicate their surnames. Appears in parentheses, you can use&; Symbol. If it appears in the text, you must use and.

The theory of sexual selection has been used to explore the mating patterns of insects (Alcock & thornhill,1983). ?

Alcock and Thornhill (1983) also proved that …

2. Cite documents without authors.

If the title of the document does not appear in the body, you should use parentheses or (if the title is too long) use the keyword group in the title, such as?

(Sleep Medicine, 200 1) or ("mad cow", 200 1).

According to APA specification, titles of independent publications or keyword groups in titles are marked in italics, and titles of works included in publications and unpublished works (speeches, papers, etc.). ) or keyword groups in the title are marked with quotation marks. When using keyword groups, you should choose the phrase at the beginning of the title.