Perhaps you should try some spelling variations:
working papers » working paper
oecd regional » world regional
chad regional » chad region
oecd regions » oecd reviews

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: ((((oecd regional) OR (oecd regions))) OR (chad regional)) economic AND development developing (leed) working papers.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((oecd regional) OR (oecd regions))) or (chad regional)) economic and development developing (leed) working papers".
• Adding a wildcard symbol may retrieve word variants: ((((oecd regional) OR (oecd regions))) or (chad regional)) economic and development developing (leed) working papers*.