Perhaps you should try some spelling variations:
"international workers economy series" » "international worker economy series", "international borders economy series", "international markets economy series", "international workers economic series", "international worker economic series", "international world's economy series"
"international plant economics series" » "international peace economics series", "international panel economics series", "international migrant economics series", "international land economics series", "international plants economic series", "international grants economics series"

Try widening your search to All Fields.

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• Performing a fuzzy search may retrieve terms with similar spellings: (("international workers economy series") or ("international plant economics series"))~.
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