APA Citation Style

In APA format, the source indicates where readers can retrieve the cited work. Sources fall into two categories, just as titles do. Works that are part of a greater whole and works that stand alone. The requirements for each one are as follows:

• the source for works that are part of a greater whole (journal article, edited book chapter, etc.) is the greater whole (i.e., the journal), and the DOI or URL
• the source for works that stand alone (book, report, dissertation, film, social media site, webpage, etc.) includes the publisher of the work, database, social media page, or website, and the DOI or URL

The general guidelines for formatting the source in an APA style reference are listed below:

• print books require the book publisher
• online books require the book publisher and the DOI or URL
• print journals require the journal name, volume number, issue number, and page range
• online journals require the journal name, volume number, issue number, page range, and the DOI or URL
• italicize the journal title and the volume number
• place the issue number in parentheses after the volume number with no space in between them

From APA Publication Manual, 7th, ed., Ch. 9.23 Definition of Source, 9.24 Format of the Source Element, & 9.25 Periodical Sources

Source element for an online journal article:

McCauley, S. M., & Christiansen, M. H. (2019). Language learning as language use: A cross-linguistic model of child language development. Psychological Review, 126(1), 1-51. https://doi.org/10.1037/rev0000126

Source information for a book:

Garton, A. (2005). Exploring cognitive development: The child as problem solver. Blackwell.