APA Edition Citation

Wills, R., & Szkutnix, L. L. (1974). Helping verbs. Longman.

Chicago Edition Citation

Wills, Roger, and L. L. Szkutnix. Helping Verbs. London: Longman, 1974.

MLA Edition Citation

Wills, Roger, and L. L. Szkutnix. Helping Verbs. Longman, 1974.

Warning: These citations may not always be 100% accurate.