Perhaps you should try some spelling variations:
reformen von » formen von, reform von, referaten von
long thanh » luong thanh, long han, long trinh
wang wang » wang yang, wang liang, wang yan
hong than » hong tan, hong hai
wan wang » wen wang, yan wang, wang yang
wang wei » zhang wei, wang zhi
form von » formen von

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 wang wei ((reformen von) OR (form von)) david ((hong than) OR (long thanh)) ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wan wang wang wei ((reformen von) or (form von)) david ((hong than) OR (long thanh)) ;~".
• Adding a wildcard symbol may retrieve word variants: wan wang wang wei ((reformen von) or (form von)) david ((hong than) OR (long thanh)) ;*.