O'Neill, R., & Richard O'Neill. (2014). Unlock: Listening and speaking skills. Cambridge: Cambridge University Press.
Trích dẫn kiểu ChicagoO'Neill, Richard, và Richard O'Neill. Unlock: Listening and Speaking Skills. Cambridge: Cambridge University Press, 2014.
MLA引文O'Neill, Richard, và Richard O'Neill. Unlock: Listening and Speaking Skills. Cambridge: Cambridge University Press, 2014.
警告：這些引文格式不一定是100％准確.