Perhaps you should try some spelling variations:
vertical integration » regional integration
integration theories » integration theory, integration through, integration efforts
integration series » integrating services, integration schemes, integration social
support vertical » support technical, airports vertical, support services
fare integration » market integration, trade integration, data integration
support fare » support falls, support state, support trade

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( support vertical integration theories. ) or ( support fare integration series. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( support vertical integration theories. ) OR ( support fare integration series. )).
• Adding a wildcard symbol may retrieve word variants: (( support vertical integration theories. ) or ( support fare integration series. ))*.