In-text parenthetical citations in APA use only the author’s last name and the publication year, but this can create confusion if you have multiple sources from the same author published in the same year. Use the following system to differentiate between such sources.
Two Sources with the Same Author and the Same Publication Year
Order citations on the References page from oldest to newest, and then identify the first (oldest) entry of the year with the letter “a” directly after the year; the second entry will be “b” and so on.
In-text Citation Example
Daniel Creel (2017b), a dietician and psychologist, suggested that being warm and empathetic can create positive relationships with people struggling with weight issues. Creel (2017a) has also argued that dieticians should shift from seeing themselves as educators to guides, which can help alleviate frustration with noncompliant patients.
References Page Entries
Creel, D. B. (2017a, January 13). Relinquishing your role as the food police. RD Lounge. https://rdlounge.com/2017/01/13/relinquishing-your-role-as-the-food-police/
Creel, D. B. (2017b, November 30) Obesity: Communicating with respect. RD Lounge. https://rdlounge.com/2017/11/30/obesity-communicating-with-respect/
Multiple Sources with the Same Author (Including Owners or Sponsors as Authors) and No Date
Order citations in alphabetical order, and then identify the first entry with the letter “a” and a hyphen directly after the n.d.; the second entry will be “b” and a hyphen, and so on.
In-text Citation Example
Whole Foods expressed their belief in “long-term thinking” as a value for leaders (Whole Foods Market, n.d.–b), which corresponds with their branding as a company committed to organic products (Whole Foods Market, n.d.–c) and “environmental stewardship” (Whole Foods Market, n.d.–a).
References Page Entries
Whole Foods Market. (n.d.- a). Our core values. Retrieved December 15, 2019, from https://www.wholefoodsmarket.com/mission-values/core-values
Whole Foods Market. (n.d.- b). Our leadership principles. Retrieved December 3, 2019, from https://www.wholefoodsmarket.com/our-leadership-principles
Whole Foods Market. (n.d.- c). Your certified organic grocer. Retrieved November 30, 2019, from https://www.wholefoodsmarket.com/about-our-products/organic-food/organicgrocer