Perhaps you should try some spelling variations:
2.1 sources » 2.2 sources, 5.2 sources, 3.2 sources
2 politics » 3 politics, 2 political, 2 politische
21 sources » 21 source, 21 resources, 2.2 sources
11 sources » 10 sources, 13 sources, 3 sources

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: %((22new spain) OR (new spain)) %2 politics AND government %2f 18th century %((2 sources) OR (((21 sources) OR (((11 sources) OR (2.1 sources))))))%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%((22new spain) or (new spain)) %2 politics and government %2f 18th century %((2 sources) or (((21 sources) or (((11 sources) OR (2.1 sources))))))%22".
• Adding a wildcard symbol may retrieve word variants: %((22new spain) or (new spain)) %2 politics and government %2f 18th century %((2 sources) or (((21 sources) or (((11 sources) OR (2.1 sources))))))%22*.