APA Style: Basics

If an author was the lead author for multiple publications that were published in the same year, the in-text citations would be identical. To address this, the APA indicates that you should include as many names as needed to distinguish the sources before using "et al.". For example, these are the authors of three studies you found in your research:

• Smith, A. A., Lieth, B. B, Cleary, C. C., & Stevens, D. D. (2019)
• Smith, A. A., Lieth, B. B, Johnson, C. C., & Tembly, D. D. (2019)
• Smith, A. A., Gilbert, B. B, White, C. C., & Schmidt, D. D. (2019)

Normally each of these would be shortened to Smith et al. (2019). Instead you want to include several names until the reader can distinguish each of the sources:

When an author or author(s) published multiple sources in the same year, include a lowercase letter immediately following the date. Begin this lettering with "a" and continue in alphabetical order.

If the first authors of multiple in-text references have the same last name, but not the same initials, include the first authors' initials in all in-text citations, even if the publication year is different. For example, the following are authors of sources you found for your paper:

• Singh, J. M. (2013)
• Singh, R. W. (2013)
• Maybell, K. L., & Choudry, L. N (2015)
• Maybell, E. N. (2020)