Perhaps you should try some spelling variations:
wei referaten » den referaten, des referates
wang liang » wang yang
liang wei » xiang wei, zhang wei, wang wei
jan david » juan david, sahn david, alan david
ben david » bevan 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.

• Performing a fuzzy search may retrieve terms with similar spellings: wan wang liang wei referaten ((jan david) or (ben david)) ng tan ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: wan wang liang wei referaten ((jan david) OR (ben david)) ng tan ;*.