Friedlaender, A. (1989). German in three months. Hugo's Language Books Ltd..
芝加哥风格引文Friedlaender, Ann. German in Three Months. Britain: Hugo's Language Books Ltd., 1989.
MLA引文Friedlaender, Ann. German in Three Months. Hugo's Language Books Ltd., 1989.
警告：这些引文格式不一定是100％准确.