Kenneth G. Wilson (1923). The Columbia Guide to Standard American English. 1993.
-s, -es
The regular plural endings for nouns are -s or -es and pronounced -s, -z, or -iz, as in cats, dogs, and churches. The third person singular present tense endings for verbs are spelled and pronounced the same way, as in hits, throws, and cashes. See PLURALS OF NOUNS.