Perhaps you should try some spelling variations:
"world board working paper" » "world word working paper", "world hard working paper", "world cold working paper", "world toward working paper", "works board working paper", "world born working paper", "world board working papers"
"world band working paper" » "world bandes working paper", "world based working paper", "world hard working paper", "world brand working paper", "world bond working paper", "world hand working paper", "world band working papers"
"world bank working paper" » "world black working paper", "world manko working paper", "world pack working paper", "world bank 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 band working paper") OR ("world board working paper"))) OR ("world bank working paper")).
• Removing quotes may allow a broader search: (((( world band working paper ) or ( world board working paper ))) or ( world bank working paper )).
• Adding a wildcard symbol may retrieve word variants: (((("world band working paper") or ("world board working paper"))) or ("world bank working paper"))*.