Cita APA (7a ed.)

Twaddell, W. F. (1963). The english verb auxiliaries (2a ed.). Brown University Press.

Cita Chicago Style (17a ed.)

Twaddell, W. F. The English Verb Auxiliaries. 2a ed. Rhode Island: Brown University Press, 1963.

Cita MLA (9a ed.)

Twaddell, W. F. The English Verb Auxiliaries. 2a ed. Brown University Press, 1963.