Meaning Digital Object Identifier, a DOI is a unique tag assigned to an article. Always include the DOI in an APA citation. But what if there is no DOI?
See these resources from The American Psychological Association to write your paper in APA Style
Full-text journal article from a database:
Owens, H., Christian, B., & Polivka, B. (2017). Sleep behaviors in traditional-age college students: A state of the science
review with implications for practice. Journal of the American Association of Nurse Practitioners, 29(11),
695-703. http://dx.doi.org/10.1002/2327-6924.12520
Ebook:
Burgess, R. (2019). Rethinking global health: Frameworks of power. Routledge.
Website:
Centers for Disease Control and Prevention. (2021, November 18). People at high risk of developing flu-related
complications. https://www.cdc.gov/flu/highrisk/index.htm
Provide surnames and initials for up to and including 20 authors. When there are two to 20 authors, use an ampersand before the final author's name. When there are 21 or more authors, include the first 19 author's names, insert an ellipsis (but no ampersand), and then add the final author's name.
In-text citations:
Reference list:
Vos, T., Lim, S. S., Abbafati, C., Abbas, K. M., Abbasi, M., Abbasifard, M., Abbasi-Kangevari, M., Abbastabar, H., Abd-Allah, F., Abdelalim, A., Abdollahi, M., Abdollahpour, I., Abolhassani, H., Aboyans, V., Abrams, E. M., Abreu, L. G., Abrigo, M. R. M., Abu-Raddad, L. J., Abushouk, A. I., … Murray, C. J. L. (2020). Global burden of 369 diseases and injuries in 204 countries and territories, 1990–2019: A systematic analysis for the Global Burden of Disease Study 2019. The Lancet, 396(10258), 1204–1222. https://doi.org/10.1016/S0140-6736(20)30925-9
Cochrane Review:
Lane, D. A., & Lip, G. Y. H. (2013). Treatment of hypertension in peripheral arterial disease. Cochrane Database of Systematic Reviews. https://doi.org/10.1002/14651858.CD003075.pub3
Clinical practice guideline with a group author
National Institute for Health and Care Excellence. (2019). Hypertension in adults: Diagnosis and management (NICE Guideline NG136). https://www.nice.org.uk/guidance/ng136
Drug information
Sandoz. (n.d.). Prednisolone acetate (prednisolone acetate) suspension/drops [Drug information]. Guideline Central. https://www.guidelinecentral.com/share/drug-information/61314-637#section-title
Lab or diagnostic manual
Pagana, K. D., Pagana, T. J., & Pagana, T. N. (2019). Mosby’s diagnostic and laboratory test reference (14th ed.). Elsevier.
For more examples and guidance, visit the APA's guide for Clinical Practice References here.
Book:
Coltrane, S. (1998). Gender and families. Pine Forge Press.
Book with two authors:
Goulding, M., & Mahar, D. (1996). Floods of fortune: Ecology and economy along the Amazon. Columbia University Press.
Journal article:
Egan, S. E., & Perry, D. G. (2001). Gender identity: A multidimensional analysis with implications for psychosocial
adjustment. Developmental Psychology, 37(4), 451-464. https://doi.org/10.1037/0012-1649.37.4.4514
Essay in a multivolume work (each volume with a unique title):
Bloom, L. Z. (1985). Maya Angelou. In T. M. Davis & T. Harris (Eds.), Dictionary of literary biography: Vol 38
Afro-American writers after 1955: Dramatists and prose writers. Gale.
Article in a reference work:
Diabetes. (2000). In The Columbia encyclopedia (6th ed., p. 2533). New York, NY: Columbia University Press.
From Publication manual of the American Psychological Association, 7th ed., p. 258, section 8.6:
"Cite secondary sources sparingly—for instance, when the original work is out of print, unavailable, or available only in a language that you do not understand. If possible, as a matter of good scholarly practice, find the primary source, read it, and cite it directly rather than citing a secondary source.
"When citing a secondary source, provide a reference list entry for the secondary source that you used. In the text, identify the primary source and then write “as cited in” the secondary source that you used. If the year of publication of the primary source is known, also include it in the text. For example, if you read a work by Lyon et al. (2014) in which Rabbitt (1982) was cited, and you were unable to read Rabbitt’s work yourself, cite Rabbitt’s work as the original source, followed by Lyon et al.’s work as the secondary source. Only Lyon et al.’s work appears in the reference list.
"(Rabbitt, 1982, as cited in Lyon et al., 2014)
"If the year of the primary source is unknown, omit it from the in-text citation.
"Allport’s diary (as cited in Nicholson, 2003)"