Perhaps you should try some spelling variations:
"harvard id case studies fuel sources." » "harvard id case studies from sources.", "harvard id case studies food sources.", "harvard id case studies led sources.", "harvard id case studies fuel source.", "harvard aids case studies fuel sources."
"harvard bond rate studies book series." » "harvard bond tracer studies book series.", "harvard bond cases studies book series.", "harvard bond graduate studies book series.", "harvard bond rate studies from series.", "harvard bank rate studies book series."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("harvard id case studies fuel sources.") or ("harvard bond rate studies book series."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("harvard id case studies fuel sources.") OR ("harvard bond rate studies book series.")).
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• Adding a wildcard symbol may retrieve word variants: (("harvard id case studies fuel sources.") or ("harvard bond rate studies book series."))*.