Perhaps you should try some spelling variations:
"western european sources." » "western europe sources.", "eastern european sources.", "eastern europe sources.", "western european series.", "western european southern.", "western european journal."
"western european studies." » "western europe studies.", "eastern european studies.", "eastern europe studies."
"western crop studies." » "western crops studies.", "western cross studies.", "western europe studies.", "western group studies.", "western erp studies.", "western hop 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 european sources.") or ((("western european studies.") or ("western crop studies."))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("western european sources.") OR ((("western european studies.") OR ("western crop studies.")))).
• Removing quotes may allow a broader search: (( western european sources. ) or ((( western european studies. ) or ( western crop studies. )))).
• Adding a wildcard symbol may retrieve word variants: (("western european sources.") or ((("western european studies.") or ("western crop studies."))))*.