Perhaps you should try some spelling variations:
"western european sources." » "eastern european sources.", "eastern europe sources.", "western european studies.", "western european series.", "western european southern."
"western europe sources." » "eastern europe sources."
"western crops studies." » "western blots studies.", "western cape studies.", "western corn studies.", "western crop studies.", "western cross studies.", "western across studies."

Try widening your search to All Fields.

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

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