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Geosciences Subject Guide

This guide will get you started with basic research on the geosciences.

Citing Resources in GSA Style

The Geological Society of America is the citation style used for this course. The GSA guidelines and several examples can be found here.


Zotero is a citation management app. With Zotero, you can keep a record of the information sources you find and format citations in a variety of styles, including GSA. For more information, visit our guide to Zotero or the Zotero site.

Specific Information about In-Text citations

With the GSA Style, quotations and borrowed phrases are indicated as such within the text, with the author's name and page number cited in parentheses. This variation is used instead of footnotes or endnotes.

When quoting or paraphrasing an author, begin the sentence by including the author's name followed by the date of publication in parentheses. At the end of the quote or paraphrase, include the page number(s) in parentheses. See example below.

According to Smith (2008), "warmer ocean temperatures can lead to the development of stronger hurricanes" (p. 133).

If the name of the author is not included within the sentence, include the author's name and the publication year at the end of the sentence with the relevant page number(s). For example:

"Warmer ocean temperatures can lead to the development of stronger hurricanes" (Smith, 2008, p. 133).


Multiple Authors:

To cite a publication with two authors, include both authors' last names either within the sentence or in parentheses at the end of the sentence.

For publications with 3-5 authors, include the last name of each author the first time the publications is cited. For subsequent citations include only the last name of the first author and the phrase et al.

For publications with 6 or more authors, list the name of the first author followed by the phrase et al. for all citations.

Specific Information about Bibliographies

  • The bibliography is arranged in alphabetical order by authors’ last names.
  • The author always comes first with last name followed by first initial, separated with a comma. Names of subsequent authors are written naturally. For four or more authors, the abbreviation “et al.” (“and others”) is used after the name of the first author.
  • Second and all subsequent lines are always indented.
  • Authors' first and middle names are never spelled out in the GSA style. Initials are always used for first and middle names.


Thanks to original author Kayla Birt for giving permission to use the content on this page, courtesy of the Dickinson College Citing Sources guide.