Allen, B. (1996). Sprechspiegel III Lernprogramm. : IBM - International Business Machines Corporation.
Chicagoスタイル(17版)引用形式Allen, Barbara. Sprechspiegel III Lernprogramm. Ireland: : IBM - International Business Machines Corporation, 1996.
MLA(8版)引用形式Allen, Barbara. Sprechspiegel III Lernprogramm. : IBM - International Business Machines Corporation, 1996.
警告: この引用は必ずしも正確ではありません.