Perhaps you should try some spelling variations:
classical sources » classical studies, classical spaces
sources library » source library, resource library, studies library
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 core library )).
• Adding a wildcard symbol may retrieve word variants: (( classical sources library ) or ( classical core library ))*.