- APA Overview
- In-Text Citations
- Reference List
- Other APA Style Issues
- Templates for Writing
Citing Multiple Sources from an Author with the Same Year
You will need to differentiate between sources with the same author and publication date by adding a lower-case letter to the publication year. Including this lower-case letter ensures that the reader knows which source you are citing in-text and can find that source in your reference list.
Add the lowercase letter immediately after the publication year in reference entries:
Centers for Disease Control and Prevention. (2011a). Birth defects. Retrieved April 26, 2011, from http://www.cdc.gov/ncbddd/birthdefects/index.html
Centers for Disease Control and Prevention. (2011b). Calcium and bone health. Retrieved April 26, 2011, from http://www.cdc.gov/nutrition/everyone/basics/vitamins/calcium.html
Centers for Disease Control and Prevention. (2011c). Prevent diabetes. Retrieved April 26, 2011, from http://www.cdc.gov/diabetes/consumer/prevent.htm
*Note that we have listed these entries alphabetically by title, with the lower-case letters assigned based on this order.
Within in-text citations, you will keep the lowercase letter with the publication year:
(Center for Disease Control, 2011a) or According to the Center for Disease Control (2011b)…
APA Style FAQ
In addition to the information provided here, refer to page 186 in the APA Manual (Sixth Edition) for how to cite and reference nonroutine information and titles.
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