Person.—There are three persons (first, second, and third) in the indicative, subjunctive, and optative. The imperative has only the second and third persons.
a. Except in a few cases in poetry ( cross465 c) the first person plural is used for the first person dual.
Herbert Weir Smyth [n.d.], A Greek Grammar for Colleges; Machine readable text [info] [word count] [Smyth].