Eckhard-Black, C., & Whittle, R. (1992). Cassell's contemporary German: A handbook of grammar current usage, and word power. Macmillan.
Chicago-viite (17. p.)Eckhard-Black, Christine, ja Ruth Whittle. Cassell's Contemporary German: A Handbook of Grammar Current Usage, and Word Power. New York: Macmillan, 1992.
MLA-viite (9. p.)Eckhard-Black, Christine, ja Ruth Whittle. Cassell's Contemporary German: A Handbook of Grammar Current Usage, and Word Power. Macmillan, 1992.
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