Cita APA (7th ed.)

KIMBROUGH, V. F., & VAI, M. (1991). English on call level one. McGraw-hill.

Cita Chicago (17th ed.)

KIMBROUGH, Victoria F., i Marjorie VAI. English on Call Level One. New York: McGraw-hill, 1991.

Cita MLA (9th ed.)

KIMBROUGH, Victoria F., i Marjorie VAI. English on Call Level One. McGraw-hill, 1991.