Perhaps you should try some spelling variations:
harvard world » harvard cold
studies force » studies formal, studies from, studies food
force surveys » force survey, firm surveys
harvard clld » harvard cold, harvard camp
study book » studies book
clld urban » led urban

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 bank study book series. ) or ( harvard clld urban studies force surveys. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( harvard world bank study book series. ) OR ( harvard clld urban studies force surveys. )).
• Adding a wildcard symbol may retrieve word variants: (( harvard world bank study book series. ) or ( harvard clld urban studies force surveys. ))*.