The Nelson First Certificate Course
Morris, Susan, Stanton, Alan

Increase your wordpower key
Woxbrandt / Kunze

Advanced Exercises in Grammar 2
Thomson, A.J./ Martinet A.V.

Visual Dictionary
Merriam-Webster's

Bürowörterbuch
Langenscheidt

B for Business
Cullen, William ua

Looking at literature
Woxbrandt / Kunze

Export English
Norman

English Synonyms
Ruff

Englisch für dich 1
Ribitsch, Horst