When quoting an entire source, only the author and year of publication are required. However, when using a direct quote from a source, the author, year and page number(s) are required for the citation. In both citations the author name may be included in the text or in the parenthetical reference. For sources such as websites and e-books that have no page numbers, use a paragraph number, part, or section. More information on citing sources without pagination is given on the APA Style web page.
APA Publication Manual pp. 261-269, Section 8.10-8.22
Two Authors:
When a work has two authors, both names should be cited every time the reference occurs in the text.
Examples:
Tyler and Simpson (2008) investigated...
(Tyler and Simpson, 2008)
Three or More Authors:
When you cite a work with three or more authors, include the name of only the first author plus 'et. al.'
Examples:
Woodbank et al. (2010) found...
(Woodbank et al., 2010)
APA Publication Manual pp. 266, Section 8.17
If you cite multiple works by different authors in one parenthetical reference, cite each work in parentheses as you normally would, place in alpahabetical order and use semicolons to separate the citations.
Example: Several studies (Miller, 2005; Shafranske & Mahoney, 2010)...
Two or more works by the same author should be arranged by year. Place citations with no date first.
Example: Past research (Gogel, n.d., 1990, 2006)...
Works written by the same author(s) and published in the same year should include a suffix, a, b, c, etc., added after the year.
Example: Several studies (Derryberry & Reed, 2005a, 2005b; Rothbart et al, 2003a, 2003b)...
APA Publication Manual pp. 263-264, Section 8.12
When citing sources by different authors who have the same last name, include the author's first initials in all in-text citations.
Example: Among studies we review M. A. Light (2008) and I. Light (2006).
APA Publication Manual p. 267, Section 8.20
For general mention of a website with no particular information or connection to a specific page from the website, a reference list entry or in-text citation is not needed. Provide the name of the website in the text with the URL in parentheses.
Cite web pages in text as you would any other source, using the author and date if known. If the author is not known, use the title and the date as the in-text citation (for long titles just use the first few words). Your in-text citation should lead your reader to the corresponding entry in the reference list. For sources with no date use n.d. (for no date) in place of the year: (Hanson, n.d.).
Examples:
Web page with author:
Role-play can help children learn techniques for coping with bullying (Kraiser, 2011).
Web page with no author:
Voting rights were limited until the year 1927 ("Voting," 2017).
Web page with no date:
Establishing regular routines, such as exercise, can help survivors of disasters recover from trauma (American Psychological Association [APA], n.d.).
When using parenthetical documentation for in-text citations, remember that sources cited in the text must point to specific sources on the References page.
When citing a Twitter or Facebook feed as a whole or to discuss it in general, you want to include the author or group name with n.d. for the date. A corresponding citation on the Reference list* will include a retrieval date as the contents of the pages can change over time.
Examples:
Parenthetical citation: APA Style (n.d.)
Narrative citation: APA Style (n.d.)
When citing specific Twitter posts and Facebook updates, citations should be included on the References list*. Corresponding in-text citations should follow the (Author, Year) example.
Example: President Obama announced the launch of the American Graduation Initiative (Obama, 2009a). He also stated that he was “humbled” to have received the Nobel Peace Prize (Obama, 2009b).
*See Reference Examples for how to cite a Twitter post or Facebook update.
APA Manual pp. 349-350, Section 10.15