Perhaps you should try some spelling variations:
"airports vertical integration series." » "airports regional integration series.", "airports vertical integration theories.", "airports vertical integrating services.", "airports vertical integration schemes.", "airport terminal integration series."
"support fare integration series." » "support fare integration theories.", "support fare integrating services.", "support fare integration schemes.", "support market integration series.", "support trade integration series.", "support data integration series.", "support falls integration series.", "support state integration series."

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: (("airports vertical integration series.") OR ("support fare integration series."))~.
• Removing quotes may allow a broader search: (( airports vertical integration series. ) or ( support fare integration series. ))~.
• Adding a wildcard symbol may retrieve word variants: (("airports vertical integration series.") or ("support fare integration series."))*.