Perhaps you should try some spelling variations:
"world macros working paper" » "world ratios working paper", "world mac working paper", "world machines working paper", "word macros working paper", "world across working paper", "world microbes working paper", "world marks working paper", "world macs working paper", "world macros working papers"
"world manko working paper" » "world django working paper", "world manner working paper", "world manual working paper", "world make working paper", "world mark working paper", "world man working paper", "world manko working papers"
"world macro working paper" » "world mac working paper", "world avro working paper", "world across working paper", "word macro working paper", "world mark working paper", "world macro working papers"
"world many working paper" » "world money working paper", "world way working paper", "world day working paper", "world may working paper", "world map working paper", "world maps working paper", "world many working papers"

Try widening your search to All Fields.

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 many working paper"))) OR ((("world macro working paper") OR ("world macros working paper")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"world manko working paper\") OR (\"world many working paper\"))) or (((\"world macro working paper\") or (\"world macros working paper\"))))".
• Removing quotes may allow a broader search: (((( world manko working paper ) OR ( world many working paper ))) or ((( world macro working paper ) or ( world macros working paper )))).
• Adding a wildcard symbol may retrieve word variants: (((("world manko working paper") OR ("world many working paper"))) or ((("world macro working paper") or ("world macros working paper"))))*.