Cita APA (7th ed.)

SMITH, C. B., & WARDHAUGH, R. (1980). Signals. Macmillan.

Cita Chicago (17th ed.)

SMITH, Carl B., i ROnald WARDHAUGH. Signals. New York: Macmillan, 1980.

Cita MLA (9th ed.)

SMITH, Carl B., i ROnald WARDHAUGH. Signals. Macmillan, 1980.