Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
between each, between every
Between can be followed by a singular noun (He changed his shirt between every inning), but this use is idiomatic, appropriate at the Conversational and Informal levels, rather than at the Oratorical and the Formal, which always prefer the full logic of between with plural nouns (between innings) or the more explicit after each inning.
