(2017). Delta Academic Objectives - Reading Skills B2-C1: Coursebook. Ernst Klett Sprachen GmbH.
芝加哥风格引文Delta Academic Objectives - Reading Skills B2-C1: Coursebook. Germany: Ernst Klett Sprachen GmbH, 2017.
MLA引文Delta Academic Objectives - Reading Skills B2-C1: Coursebook. Ernst Klett Sprachen GmbH, 2017.
警告：这些引文格式不一定是100％准确.