Perhaps you should try some spelling variations:
symposium sieds » symposium series, symposium sas, symposium sss
das symposium » das symposion, bacus symposium, texas symposium
symposium irs » symposium iv, symposium i, symposium ii

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: (( das symposium irs ) OR ( das symposium sieds )).
• Adding a wildcard symbol may retrieve word variants: (( das symposium irs ) or ( das symposium sieds ))*.