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BY 429/491/629: Evolutionary Biology In-Text Citations

In-Text Citations

In-text citations appear within the body of the paper and briefly identify the cited works by author name and publication year.  For more information, consult the in-text citation guidelines.

There are two formats for in-text citations:

Parenthetical Citation

  • author name and publication year appear in parentheses separated by a comma
  • usually appear at end of the sentence (can also appear within the sentence)

Human infection with Vibrio cholera, a gram-negative motile rod causing cholera, begins with ingestion of contaminated food or water containing the bacterium (Halpern & Izhaki, 2017).

Vibrio cholera may have a mutualistic relationship with fish since they “provide food and shelter for this bacterium while the bacterium may assist the fish to digest its food” (Halpern & Izhaki, 2017, p. 5).

Narrative Citation

  • author name is incorporated into the text as part of the sentence and the publication year follows in parentheses
  • usually appear at beginning of the sentence (can also appear within or at end of the sentence)

According to Halpern and Izhaki (2017), human infection with Vibrio cholera, a gram-negative motile rod causing cholera, begins with ingestion of contaminated food or water containing the bacterium.

Halpern and Izhaki (2017) state that Vibrio cholera may have a mutualistic relationship with fish since they “provide food and shelter for this bacterium while the bacterium may assist the fish to digest its food” (p. 5).

For more information, consult the parenthetical versus narrative in-text citation guidelines.


The formatting of in-text citations varies depending on the number of authors.

Author type Parenthetical citation Narrative citation
One author (Derby, 2020) Derby (2020)
Two authors (Aggio & Kamio, 2020) Aggio and Kamio (2020)
Three or more authors (Johnson et al., 2020) Johnson et al. (2020)
Group author (Harvard University, 2020) Harvard University (2020)

Group author with abbreviation

     First citation

     Subsequent citations

 

(World Health Organization [WHO], 2020)

(WHO, 2020)

 

World Health Organization (WHO, 2020)

WHO (2020)

For more information, consult the author-date citation system guidelines.