Παραπομπή APA

Allen, H. (1939). Commercial arithmetic. Longmans, Green and Co.

Παραπομπή Chicago Style

Allen, H.V. Commercial Arithmetic. London: Longmans, Green and Co, 1939.

Παραπομπή MLA

Allen, H.V. Commercial Arithmetic. Longmans, Green and Co, 1939.