Perhaps you should try some spelling variations:
recursion library » section library, recursion summary, equation library
decision library » section library, decision hierarchy, education library
vision library » design library, vision linear, visual library
gson library » open library, own library, town library

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: theory AND ((((decision library) OR (recursion library))) OR (((vision library) OR (gson library)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "theory and ((((decision library) OR (recursion library))) or (((vision library) or (gson library))))".
• Adding a wildcard symbol may retrieve word variants: theory and ((((decision library) OR (recursion library))) or (((vision library) or (gson library))))*.