Perhaps you should try some spelling variations:
dem referat » zum referat
wang liang » wang yang
john david » cohen david, sahn david, juan david
liang dem » liang dan, liang wei
von david » ben david, jan david
wei wang » wei yang, wen wang, wei shang
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: wei wang liang dem referat ((von david) OR (john david)) ng tan ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wei wang liang dem referat ((von david) OR (john david)) ng tan ;*".