Perhaps you should try some spelling variations:
numerical mathematics » industrial mathematics, general mathematics
international service » international overview, international justice, international science
international series » international services, international serious, international serials
mathematik » mathematical

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 service)) of ((numerical mathematics) OR (numerische mathematik)).
• Adding a wildcard symbol may retrieve word variants: ((international series) or (international service)) of ((numerical mathematics) or (numerische mathematik))*.