Perhaps you should try some spelling variations:
international services » international service, integration services, international overview
international aerien » international african, international aktiven, international action
reserves » serves

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 aerien) OR (((international services) OR (international reserves)))) in operations research & management science.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((international aerien) or (((international services) OR (international reserves)))) in operations research & management science".
• Adding a wildcard symbol may retrieve word variants: ((international aerien) or (((international services) OR (international reserves)))) in operations research & management science*.