Perhaps you should try some spelling variations:
"world manko working paper" » "world django working paper", "world manner working paper", "world manual working paper", "world many working paper", "world make working paper", "world mark working paper"
"world macro working paper" » "world macros working paper", "world mac working paper", "world across working paper", "word macro working paper", "world mark working paper"
"world macro working papers" » "world macros working papers", "world mac working papers", "world across working papers", "word macro working papers", "world mark working papers"

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (("world manko working paper") OR ((("world macro working paper") OR ("world macro working papers"))))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"world manko working paper\") or (((\"world macro working paper\") OR (\"world macro working papers\"))))*".
• Removing quotes may allow a broader search: (( world manko working paper ) or ((( world macro working paper ) OR ( world macro working papers ))))*.