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BIOL 5030: Foundations of Environmental Science

Library resources for graduate students in Environmental Science and guidance on how to write an annotated bibliography.

Definition and Purpose of Annotated Bibliographies


An annotated bibliography is a an alphabetical or chronological list of citations with each citation followed by a paragraph that gives information about the resource. The paragraphs, or annotations, can be written in a number of styles that will be covered on the next page, Different Annotation Types.

The format of the citations and annotations is determined by the style guide you've been assigned - MLA, APA, Chicago, etc. The Libraries have both online and print style guides for you on the Citations and Style Guides page.


There are numerous purposes for writing an annotated bibliography:

  • To familiarize yourself with the literature in an area
  • To prepare to write a research paper and make a record of your impressions of the sources
  • To provide readers of your scholarly work with additional information about sources, such as author backgrounds, your evaluations, or summaries.
  • To place your research in a historical context for readers

Annotated Bibliography - YouTube

Examples of Annotated Bibliographies

Annotations are generally 150 -200 words in length. The formatting of the annotation and the spacing between it and the citation are determined by the citation style you select. Many styles call for a hanging indent, meaning the first line is at the margin and the subsequent lines are moved in a designated number of spaces.

To see annotations in APA, MLA, and Chicago styles, see the examples at the Purdue OWL website. APA does not have a definitive style for annotated bibliographies, according to the APA Style blog, so use whichever suggested APA format your instructor likes best. 

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