Perhaps you should try some spelling variations:
"christian gottlieb frege" » "christoph gottlieb frege", "christian gottlob frege", "christian gottlieb roger", "christian gottlieb green"
"christian gottlob frage" » "christian gotthilf frage", "christian gottlob frege", "christian gottlob kruger"

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: (("christian gottlob frage") OR ("christian gottlieb frege")).
• Removing quotes may allow a broader search: (( christian gottlob frage ) or ( christian gottlieb frege )).
• Adding a wildcard symbol may retrieve word variants: (("christian gottlob frage") or ("christian gottlieb frege"))*.