2003, Douglas Lorain, “Milo McIver State Park Loop”, in Laura Shauger, editor, Afoot & Afield Portland/Vancouver: A comprehensive hiking guide, Wilderness Press, →ISBN, page 402:
Turn right and go uphill on a wide trail that is pleasant despite being chopped up by hooves and made aromatic by horse apples.
2009, Gwen Petersen, edited by Margret Aldrich, EVERYTHING I Know About Life I Learned From MY HORSE, Voyageur Press, →ISBN, page 182:
The string somehow went unnoticed among the horse apples. One end of the twine sank its tail deeply into the mire and froze there, resisting all your efforts to pull it out.
2014, Darcy Pattison, chapter 4, in Kell and the Horse Apple Parade, Mims House:
When everyone was seated, the Mayor said, “What will you do about the horse apples?” ¶ “Um,” Mom said. ¶ “I don’t want poop left all over my streets.” ¶ “What?” I was confused. ¶ “Horse apples,” the Mayor said. ¶ “You know. Horse poop.”
