Perhaps you should try some spelling variations:
"international blank economic series" » "international bank economic series", "international banks economic series", "international plant economic series", "international blank economics series", "international blank economic services", "international blank economic theories", "international black economic series", "international blacks economic series"
"international open economy series" » "international hope economy series", "international order economy series", "international scope economy series", "international open economics 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: (("international open economy series") OR ("international blank economic series"))~.
• Removing quotes may allow a broader search: (( international open economy series ) or ( international blank economic series ))~.
• Adding a wildcard symbol may retrieve word variants: (("international open economy series") or ("international blank economic series"))*.