Revell, J., Phillips, D., & Sheerin, S. (1991). Signature intermediate: Workbook. [s.n].
Cita Chicago Style (17a ed.)Revell, Jane, Diane Phillips, y Susan Sheerin. Signature Intermediate: Workbook. NelSon, U.K: [s.n], 1991.
Cita MLA (9a ed.)Revell, Jane, et al. Signature Intermediate: Workbook. [s.n], 1991.
Precaución: Estas citas no son 100% exactas.