Cita APA (7a ed.)
Watkins, F., & Hiers, J. (1989). Practical English workbook (4th ed.). Houghton.
Cita Chicago Style (17a ed.)
Watkins, Floyd, y John Hiers. Practical English Workbook. 4th ed. Boston: Houghton, 1989.
Cita MLA (9a ed.)
Watkins, Floyd, y John Hiers. Practical English Workbook. 4th ed. Houghton, 1989.
Precaución: Estas citas no son 100% exactas.