A very, very brief search has given me the refs below for initial reading. I'm starting with the grammar and pragmatics. Haven't even tried to search, yet, for CDA angles.
Aikhenvald, A.Y., 2013. Imperatives and commands (Back Pages; Appendix: Imperatives and commands: how to know more: a checklist for fieldworkers), Oxford: Oxford University. Press.
Anderson, J.M., 2007. The grammar of names. Oxford: Oxford University Press.
Davies, E.E., 1986. English vocatives: A look at their function and form. Studia Anglistica Posnaniensia, 19, pp.91-106.
Downing, B.T., 1969. Vocatives and third‐person imperatives in English. Paper in Linguistics, 1(3), pp.570–592.
Formentelli, M., 2007. The vocative mate in contemporary English: A corpus based study. Language resources and linguistic theory. Milan: Franco Angeli, pp.180-99.
Zanuttini, R., Pak, M. and Portner, P., 2012. A syntactic analysis of interpretive restrictions on imperative, promissive, and exhortative subjects. Natural Language & Linguistic Theory, 30(4), pp.1231-1274.
Zwicky, A. 1974. Hey, Whatsyourname!. CLS 10, 787-800.