Perhaps you should try some spelling variations:
"harvard col tracer studies from surveys." » "harvard col tracer studies from survey.", "harvard col tracer studies firm surveys.", "harvard col tracer studies force surveys.", "harvard col traces studies from surveys.", "harvard col trace studies from surveys.", "harvard col trader studies from surveys."
"harvard world war studies book series." » "harvard world case studies book series.", "harvard world bank studies book series."

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("harvard col tracer studies from surveys.") or ("harvard world war studies book series."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("harvard col tracer studies from surveys.") OR ("harvard world war studies book series.")).
• Removing quotes may allow a broader search: (( harvard col tracer studies from surveys. ) or ( harvard world war studies book series. )).
• Adding a wildcard symbol may retrieve word variants: (("harvard col tracer studies from surveys.") or ("harvard world war studies book series."))*.