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Annotated Bibliographies

What are they & how do you write one? This guide will give you some tips.

What do you write in the annotations?

Most annotated bibliographies follow a three-part structure:

  • The full citation to the source
  • A paragraph summarizing or describing what the source says
  • A paragraph critically analyzing the source

Purdue Owl has a page describing an annotated bibliography and how the descriptive and critical paragrahs should differ.

Basically, the summary paragraph should say what a source says while the analysis paragraph should say how well it is written.

Ask your instructor if they expect something different! Not all annotated bibliographies follow this form, though it is common.

The Full Citation

This is the same as any other Bibliography or Works Cited page and should be in the citation style your instructor specified, such as APA or MLA style.

See the Citations page for more information on using NoodleBib to save yourself some time in formatting citations.

Example MLA Citation

Mortensen, Rasmus J., et al. "Characterization Of Viruses Infecting Potato Plants From A Single Location In Shetland,
                    An Isolated Scottish 
Archipelago." Journal Of Phytopathology 158.9 (2010): 633-640. Academic Search Premier.
                    Web. 29 Oct. 2014.

Example APA Citation

Mortensen, R. J., Xinyi, S., Reid, A., & Mulholland, V. (2010). Characterization of viruses infecting potato plants from a single location in Shetland, an isolated Scottish archipelago. Journal Of Phytopathology, 158(9), 633-640. doi:10.1111/j.1439-0434.2010.01672.x


The summary paragraph should relate what the source says in your own words. It should not say whether you agree with the source or not and it should not simply repeat large portions of the source. For instance:

Good Example

The article examines the DNA sequences of potato viruses in a remote location in Scotland. Four different virus infections in nine potatoes were sequenced and analyzed. The remote nature of the island archipelago studied should have caused the viruses to be distinct from those found on the main land, which was found to be true in some cases but not all.

Bad Example

"Sequence data were obtained from 29 isolates of Potato virus A (PVA), Potato virus S (PVS), Potato virus V (PVV) and Potato virus X (PVX) infecting nine tubers from Shetland, one of the most remote inhabited islands in the United Kingdom. These isolates were sequenced in the coat protein region, as were 29 Scottish mainland isolates of the same four potato virus species, and these 58 isolates were compared to previously published sequence data." I didn't like this article because I don't like potatoes, much less virus-ridden ones.


The analysis paragraph goes beyond summary to actually determine whether the source was a well-written, high-quality source. You should not offer your own opinion but make qualified arguments as to why the source was good or bad, perhaps drawing on the results of your CRAAP test earlier.

Good Example

The source uses many previous studies to back up its conclusions. Studies from the past few years are used to contrast with the viruses the researchers found, showing telling differences. While the methods of the authors' research were well-informed and accurate, they only ran their study on a few potatoes in one geographic area. Their findings should not be generalized to the world at large because they are too limited both in number of potatoes and area of the country studied.

Bad Example

I disagree with the source because I had a potato once and it didn't contract any viruses. I don't know why you'd study potato viruses. How could you even tell one was infected? I don't think you can tell that potatoes get infected and this article didn't make any sense. I couldn't read the charts showing the potato virus genes at all.