Perhaps you should try some spelling variations:
"harvard world urban studies book series." » "harvard cold urban studies book series.", "harvard worst urban studies book series.", "harvard world urban studies books series.", "harvard world urban 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.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"harvard world urban studies book series.\") OR (\"harvard world war studies fuel sources.\"))~".
• Removing quotes may allow a broader search: (( harvard world urban studies book series. ) OR ( harvard world war studies fuel sources. ))~.
• Adding a wildcard symbol may retrieve word variants: (("harvard world urban studies book series.") OR ("harvard world war studies fuel sources."))*.