Perhaps you should try some spelling variations:
"eastern european sources." » "eastern europe sources.", "east european sources.", "eastern european series.", "eastern european southern.", "eastern european journal."
"eastern european studies." » "eastern europe studies.", "east european studies."
"western europe sources." » "eastern europe sources."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((("eastern european sources.") or ("western europe sources."))) or ("eastern european studies."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("eastern european sources.") OR ("western europe sources."))) OR ("eastern european studies.")).
• Removing quotes may allow a broader search: (((( eastern european sources. ) or ( western europe sources. ))) or ( eastern european studies. )).
• Adding a wildcard symbol may retrieve word variants: (((("eastern european sources.") or ("western europe sources."))) or ("eastern european studies."))*.