Perhaps you should try some spelling variations:
wei referaten » den referaten, des referates
referaten von » referat von, referat vom, reformen von
wang liang » wang yang
liang wei » xiang wei, zhang wei, wang wei
wan wang » wen wang, yan wang, wang yang
david ng » david g, david a, david _
david n » david a, david _, david k

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 von ((david ng) OR (david n)) tan ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wan wang liang wei referaten von ((david ng) OR (david n)) tan ;*".