Perhaps you should try some spelling variations:
22income distribution » income distribution, income redistribution, genome distribution
income distributions » income distribution, income redistribution, time distributions
10 developing » 10 development
40 developing » 30 developing, 40 development
20 developing » 20 development

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: %((22income distribution) OR (income distributions)) %((((10 developing) OR (40 developing))) OR (20 developing)) countries%22.
• Adding a wildcard symbol may retrieve word variants: %((22income distribution) or (income distributions)) %((((10 developing) or (40 developing))) or (20 developing)) countries%22*.