(2017). Delta Academic Objectives - Listening and Note Taking Skills B2-C1 Coursebook with Audio CD. Stuttgart Klett Sprachen GmbH.
芝加哥风格引文Delta Academic Objectives - Listening and Note Taking Skills B2-C1 Coursebook with Audio CD. German: Stuttgart Klett Sprachen GmbH, 2017.
MLA引文Delta Academic Objectives - Listening and Note Taking Skills B2-C1 Coursebook with Audio CD. Stuttgart Klett Sprachen GmbH, 2017.
警告：这些引文格式不一定是100％准确.