Another relevant syntactic relation is agreement - namely, the relation that holds between a verb and a noun phrase that bears a grammatical function with respect to that verb, such that the morphological shape of the verb is determined in part by the grammatical features of the noun phrase (number, person, gender, etc.). [...] I will assume that agreement can be universally represented as establishing a relationship between a verb and an NP that is one of its associated grammatical functions (at a particular point in a derivation).
- Baker (2004), a pag.9