I have two sources by the same author but neither have a year of publication (they are n.d.). How do I differentiate between them?
As you may know, entries in an APA Style reference list are alphabetized first by author last name and then by year of publication. If more than one entry has the same author(s) with the same year of publication, they are then alphabetized by title. Letters (a, b, c, etc.) are added to the year of publication to differentiate the entries.
If two or more sources have the same author and the year of publication is n.d. (no date), we still use letters to differentiate between them. However, hyphens are added before the letters to improve readability.
Let’s say we had three sources by the same author, and none of them have a year of publication indicated:
Glenbow Museum. (n.d.). Our world: Videos.
Glenbow Museum. (n.d.). Our traditional territory [Image].
Glenbow Museum. (n.d.). Our world.
How would we sort them in the reference list? Well, first we would put them in alphabetical order (by title):
Glenbow Museum. (n.d.). Our traditional territory [Image].
Glenbow Museum. (n.d.). Our world.
Glenbow Museum. (n.d.). Our world: Videos.
And then, we add letters to differentiate them. Our finished reference examples would look like this:
Glenbow Museum. (n.d.-a). Our traditional territory [Image]. https://www.glenbow.org/blackfoot/maps/traditional_territory_map.htm
Glenbow Museum. (n.d.-b). Our world. https://www.glenbow.org/blackfoot/EN/html/our_world.htm
Glenbow Museum. (n.d.-c). Our world: Videos. http://www.glenbow.org/blackfoot/EN/html/videos.htm
Parenthetical citations: (Glenbow Museum, n.d.-a, n.d.-b)
Narrative citations: Glenbow Museum (n.d.-c)
Note the punctuation.
1. Put periods after both the n and the d .
2. Insert a hyphen after n.d. to differentiate it from the lettering.
3. Do not put periods after the a, b, c.