Perhaps you should try some spelling variations:
classical sources » classical studies, classical spaces
classical source » classic source, classical force, classical resources
sources library » resource library, studies library, series library
source library » source libraries
classical core » classical codes, classical case, classical charge
core library » code library, case library, core libraries

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: (((( classical sources library ) OR ( classical source library ))) OR ( classical core library )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((( classical sources library ) OR ( classical source library ))) or ( classical core library ))".
• Adding a wildcard symbol may retrieve word variants: (((( classical sources library ) OR ( classical source library ))) or ( classical core library ))*.