APA (7th ed.) Citation

Wardhaugh, R. (1995). Understanding English grammar: A linguistic approach. Blackwell Publishers.

Chicago Style (17th ed.) Citation

Wardhaugh, Ronald. Understanding English Grammar: A Linguistic Approach. Cambridge, Mass: Blackwell Publishers, 1995.

MLA (9th ed.) Citation

Wardhaugh, Ronald. Understanding English Grammar: A Linguistic Approach. Blackwell Publishers, 1995.