Perhaps you should try some spelling variations:
"eastern european sources." » "eastern european studies.", "eastern european southern.", "eastern european journal.", "western europe sources.", "fastern european sources."
"east european series." » "east european studies.", "east european cities.", "east european society.", "fast european series."
"eastern europe sources." » "fastern 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 europe sources.") OR ("eastern european sources."))) or ("east european series."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("eastern europe sources.") OR ("eastern european sources."))) OR ("east european series.")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"eastern europe sources.\") OR (\"eastern european sources.\"))) or (\"east european series.\"))".
• Removing quotes may allow a broader search: (((( eastern europe sources. ) OR ( eastern european sources. ))) or ( east european series. )).
• Adding a wildcard symbol may retrieve word variants: (((("eastern europe sources.") OR ("eastern european sources."))) or ("east european series."))*.