Perhaps you should try some spelling variations:
"sunk series in african event studies." » "sunk series in african giant studies.", "sunk series in african great studies.", "sunk series in africa recent studies."
"sunk series in african debt studies." » "sunk series in african great studies.", "sunk series in african ict studies.", "sunk series in african post studies.", "sunk series in african debt sources.", "sunk series in african cost studies.", "sunk series in african past studies."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("sunk series in african event studies.") OR ("sunk series in african debt studies."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"sunk series in african event studies.\") OR (\"sunk series in african debt studies.\"))".
• Removing quotes may allow a broader search: (( sunk series in african event studies. ) OR ( sunk series in african debt studies. )).
• Adding a wildcard symbol may retrieve word variants: (("sunk series in african event studies.") OR ("sunk series in african debt studies."))*.