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

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: (((("fastern european sources.") OR ("east european sources."))) OR ("eastern europe sources."))~.
• Removing quotes may allow a broader search: (((( fastern european sources. ) or ( east european sources. ))) or ( eastern europe sources. ))~.
• Adding a wildcard symbol may retrieve word variants: (((("fastern european sources.") or ("east european sources."))) or ("eastern europe sources."))*.