See one source in every style
Date. When it was published. Author–date styles (APA, Harvard, Chicago author-date) put it second; MLA and Chicago notes put it near the end.
APA is author–date: the year sits right after the author because in psychology and the sciences, how recent the research is matters. Titles of articles go in sentence case.
Side by side
APA: psychology, education, nursing, business, social sciences. · MLA: English, languages, literature, cultural studies. · Chicago: history, art history, philosophy, theology.
APA: (Okafor, 2022, p. 48). · MLA: (Okafor 48). · Chicago: footnote¹, or (Okafor 2022, 48) in author-date.
APA: References. · MLA: Works Cited. · Chicago: Bibliography.
APA: Okafor, M. · MLA: Okafor, Maya. · Chicago: Okafor, Maya.
APA: straight after the author. · MLA: near the end. · Chicago: near the end (notes) or after the author (author-date).
APA: sentence case. · MLA and Chicago: title case.
APA: separate title page. · MLA: no title page, a four-line heading. · Chicago: title page for most student papers.
Why they differ
Sciences build on recent findings, so APA puts the year up front: a reader scanning your references sees at a glance whether the research is current. The humanities work closely with texts, where a quote’s exact location matters more than the year, so MLA pairs author with page. Historians juggle archives, letters and editions, so Chicago’s footnotes let each claim carry its full source without cluttering the sentence.
Quick examples
Kahneman, D. (2011). Thinking, fast and slow. Farrar, Straus and Giroux.
In-text: (Kahneman, 2011, p. 79) or Kahneman (2011, p. 79)
Kahneman, Daniel. Thinking, Fast and Slow. Farrar, Straus and Giroux, 2011.
In-text: (Kahneman 79) or Kahneman (79)
Kahneman, Daniel. Thinking, Fast and Slow. Farrar, Straus and Giroux, 2011.
Footnote: Daniel Kahneman, Thinking, Fast and Slow (Farrar, Straus and Giroux, 2011), 79.