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How to write an annotated bibliography

What is an annotated bibliography?

An annotated bibliography or annotated bib is a bibliography (a list of books or other works) that includes descriptive and evaluative comments about the sources cited in your paper. These comments are also known as annotations.

How do I format my annotated bibliography?

An annotated bibliography entry consists of two components: the Citation and the Annotation.


The citation should be formatted in the bibliographic style that your professor has requested for the assignment. Some common citation styles include APA, MLA, and Chicago. For more information, see the Style Guides page.


Generally, an annotation is approximately 100-300 words in length (one paragraph). However, your professor may have different expectations so it is recommended that you clarify the assignment guidelines.

An annotation may include the following information:

  • A brief summary of the source
  • The source’s strengths and weaknesses
  • Its conclusions
  • Why the source is relevant in your field of study
  • Its relationships to other studies in the field
  • An evaluation of the research methodology (if applicable)
  • Information about the author’s background
  • Your personal conclusions about the source

MLA style format

Hanging Indents are required for citations in the bibliography, as shown below. That is, the first line of the citation starts at the left margin, and subsequent lines are indented 4 spaces.

The bibliography is double-spaced, both within the citation and between them.

Lozier, J. D., P. Aniello and M.J. Hickerson. "Predicting the Distribution of Sasquatch in Western North America:

Anything Goes With Ecological Niche Modelling." Journal of Biogeography 36.9 (2009): 1623-1627. Academic

Search Premier. Web. 28 Jan. 2010.


This paper critiques the use of Ecological Niche Models (ENM) and species distribution by performing a tongue-

in-cheek examination of the distribution of the fictional Sasquatch, based on reports from an online Bigfoot archive.

Lozier's paper powerfully demonstrates the issues faced by ENM, when reports come from non-specialists, and

highlights key problems with sourcing data from unmediated online environments. The author neglects to compare

the reliability of the many wildlife databases with the single Bigfoot database, as well as other key issues; however in

closing, the paper briefly mentions that many issues lie outside the scope of the short article. Lozier's paper advises

professionals in fields using ENM to carefully assess the source of the data on which the model is based and

concludes that the distribution of rare species in particular is often over-reported to misidentification.


APA style format

Hanging Indents are required for citations in the bibliography, as shown below. That is, the first line of the citation starts at the left margin, and subsequent lines of the citation are indented 4 spaces.

The annotation is indented 2 additional spaces, as a block.

D’Elia, G., Jorgensen, C., Woelfel, J., & Rodger, E. J. (2002). The impact of the Internet on public library use: An analysis of the current

consumer market for library and Internet services. Journal of the American Society for Information Science and Technology

53(10), 808-820. doi:10.1002/asi.10102

In this study, the researchers examined if the Internet had affected public library usage in the United States. This study is

distinct because its researchers surveyed library nonusers as well as users. The major finding was that 75.2% of people

who used the Internet also used the public library. However, the researchers surveyed only 3000 individuals in a population

of millions; therefore, these results may not be statistically significant. However, this study is relevant because it provides

future researchers with a methodology for determining the impact of the Internet on public library usage.

Additional resources

Annotated bibliographies
From Purdue OWL

Writing an annotated bibliography
From Concordia University

How to prepare an annotated bibliography
From Cornell University

Writing an annotated bibliography
From University of Toronto