Perhaps you should try some spelling variations:
"harvard world case studies book series." » "harvard cold case studies book series.", "harvard world class studies book series.", "harvard world case studies books series.", "harvard world case studies ebook series."
"harvard world war studies fuel sources." » "harvard cold war studies fuel sources.", "harvard world war studies cruel sources.", "harvard world war studies field sources.", "harvard world war studies from sources.", "harvard world war studies fuel source.", "harvard world war stories fuel sources.", "harvard world early studies fuel sources."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("harvard world case studies book series.") or ("harvard world war studies fuel sources."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("harvard world case studies book series.") OR ("harvard world war studies fuel sources."))*.
• Removing quotes may allow a broader search: (( harvard world case studies book series. ) or ( harvard world war studies fuel sources. ))*.