Perhaps you should try some spelling variations:
dem referat » zum referat
wang liang » wang yang
juan david » bulman david
liang dem » liang dan, liang wei
jan david » alan david, john david, ben david
yan wang » yuan wang, yang yang, qian wang
ng tan » hong tan, wing tan

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

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