Perhaps you should try some spelling variations:
des referates » des referats, den referaten, eines referates
bevan david » evans david, bulman david
wang liang » wang yang
liang des » gang des, liang dan, liang wei
von david » john david, jan david
wan wang » wen wang, yan wang, wang yang
ng tan » hong tan, wing tan

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

• If you are trying to use Boolean operators, they must be ALL CAPS: wan wang liang des referates ((von david) OR (((ben david) OR (bevan david)))) ng tan ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wan wang liang des referates ((von david) or (((ben david) OR (bevan david)))) ng tan ;~".
• Adding a wildcard symbol may retrieve word variants: wan wang liang des referates ((von david) or (((ben david) OR (bevan david)))) ng tan ;*.