Williams, S. (1999). Focus on vocabulary. Cornelsen & Oxford.
Chicagoスタイル(17版)引用形式Williams, Steve. Focus on Vocabulary. Berlin: Cornelsen & Oxford, 1999.
MLA(8版)引用形式Williams, Steve. Focus on Vocabulary. Cornelsen & Oxford, 1999.
警告: この引用は必ずしも正確ではありません.