Perhaps you should try some spelling variations:
liang zum » zwang zum, gang zum, liang sun
drang zum » andrang zum, zwang zum, gang zum
von david » john david, ben david, jan david
wei wang » wei yang, wen wang, wei shang
wing tan » wing ian, liang tan, hong tan
ng tan » hong tan
referat » referral

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: wei wang ((liang zum) or (drang zum)) referat von david ((ng tan) OR (wing tan)) ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: wei wang ((liang zum) OR (drang zum)) referat von david ((ng tan) OR (wing tan)) ;*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wei wang ((liang zum) or (drang zum)) referat von david ((ng tan) OR (wing tan)) ;*".