A communicative grammar of English.

MLA

Leech, Geoffrey Neil, and Jan Svartvik. A Communicative Grammar of English. 3rd ed. Harlow, Essex: Pearson Education, 2002.

APA

Leech, G. Neil, & Svartvik, J. (2002). A communicative grammar of English. 3rd ed. Harlow, Essex: Pearson Education.

Chicago

Leech, Geoffrey Neil, and Jan Svartvik. A Communicative Grammar of English. 3rd ed. Harlow, Essex: Pearson Education, 2002.