Confusingly, verbs of this type have also been called unaccusative verbs, middle voice, anticausative verbs in the literature, but these terms usually have other meanings in the literature. In a useful discussion of the terminology, Dixon flat out rejects the use of the word ergative to describe such verbs, which was originated by Halladay's 1967 paper and propagated by Lyons' 1968 textbook, because the "ergativity" is contained entirely in the lexical unit and has no influence on a language's overall morphological or syntactic ergativity.