Perhaps you should try some spelling variations:
international services » international service, international reserves, integration services
international serials » international serious, international trials, international materials
international series » international serious, international aerien, international fisheries

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: ((((international series) OR (international services))) OR (international serials)) of ((industrial mathematics) OR (numerische mathematik))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((international series) OR (international services))) or (international serials)) of ((industrial mathematics) or (numerische mathematik))*".