Perhaps you should try some spelling variations:
"off working papers; working paper" » "offer working papers; working paper", "imf working papers; working paper", "office working papers; working paper"
"adf working papers; working paper" » "imf working papers; working paper", "staff working papers; working paper"
"hf working papers; working paper" » "imf working papers; working paper"

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