Twaddell, W. F. (1965). The English verb auxiliaries (2nd ed. rev.). Brown University Press.
Chicago Style (17th ed.) CitationTwaddell, W. F. The English Verb Auxiliaries. 2nd ed. rev. Providence: Brown University Press, 1965.
MLA (9th ed.) CitationTwaddell, W. F. The English Verb Auxiliaries. 2nd ed. rev. Brown University Press, 1965.
Warning: These citations may not always be 100% accurate.