How to cite newspaper articles by the same author and published on the same day in APA style?
Please take the approach suggested in "How do I cite two or more resources by the same author that were published in the same year in APA style?": In your references, order the resources with the same author and publication date alphabetically by the title of the article (excluding "a" or "the"). Then, using the order determined by the alphabetization of the resources by title, attach a lower-case letter to the year to distinguish between resources. For example:
Lastname, A. (2002a, September 22). An article in a newspaper. National Post, p. 4.
Lastname, A. (2002b, September 22). Bees making a return this summer. National Post, p. 6.
Lastname, A. (2002c, September 22). Canada looks to the next Grey Cup. National Post, p. 22.
If your resource isn't dated, you can append the lowercase letters to n.d.: n.d.-a, n.d.-b. In your in-text citations, please make sure that you're using the same lower-case letter to identify resources as you did in your references. With this system in mind, your citation would take the form of (Lastname, 2002a, p.). The day the newspaper was published isn't necessary in the citation - only the year needs to be provided. I'd recommend providing the page number of the page in the newspaper where your information can be found; however, if the article is online, doesn't have page numbers, and the URL provided in your reference takes your reader directly to the article, you could use paragraph numbers in the citation. For more information on the correct referencing format for print or online newspaper articles, please see page 200 in the Publication Manual of the American Psychological Association (American Psychological Association, 2010).
American Psychological Association. (2010). Publication manual of the American Psychological Association (6th ed.). Washington, DC: Author.