Cita APA (7a ed.)

Eckersley, C., & Kaufmann, W. (1970). English and american business letters. Longman.

Cita Chicago Style (17a ed.)

Eckersley, C.E, y W. Kaufmann. English and American Business Letters. London: Longman, 1970.

Cita MLA (9a ed.)

Eckersley, C.E, y W. Kaufmann. English and American Business Letters. Longman, 1970.