Perhaps you should try some spelling variations:
john charles » cohen charles, jean charles, von charles
charles yu » charles _, charles a, charles e
dang hadi » dang hai
yang jie » yang jin, yang jui, yang yi
yu chen » yu cheng, yi chen, yulu chen
yang li » yang lin, yang yi, tang li
yang xi » yang yi, yang jui
dugan » duggan, dusan, duran

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: dugan john charles yu chen ((((yang li) OR (yang jie))) OR (((yang di) OR (yang xi)))) dang hadi ;~.
• Adding a wildcard symbol may retrieve word variants: dugan john charles yu chen ((((yang li) or (yang jie))) or (((yang di) or (yang xi)))) dang hadi ;*.