Perhaps you should try some spelling variations:
garding's inequality » earnings inequality, hardy's inequality, young's inequality
garding inequality » earnings inequality, hardy inequality, hardy's inequality
warning inequality » earnings inequality, learning inequality, widening inequality
learning quality » learning ability
wage » wave

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: wage AND ((learning quality) OR (((((garding inequality) OR (garding's inequality))) OR (warning inequality)))).
• Adding a wildcard symbol may retrieve word variants: wage and ((learning quality) or (((((garding inequality) or (garding's inequality))) or (warning inequality))))*.