Perhaps you should try some spelling variations:
aggregate functional » aggregate function, aggregation functional, aggregates national
aggregate functions » aggregation functions
aggregate fraction » aggregate reaction, aggregate function, aggregate extraction
functions income » functional income, functions come, functions inline

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: (( aggregate functions income distribution ) OR ( ((aggregate functional) OR (aggregate fraction)) income distribution )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( aggregate functions income distribution ) or ( ((aggregate functional) OR (aggregate fraction)) income distribution ))".
• Adding a wildcard symbol may retrieve word variants: (( aggregate functions income distribution ) or ( ((aggregate functional) OR (aggregate fraction)) income distribution ))*.