Perhaps you should try some spelling variations:
"christian gottlob kruger" » "christian gottlieb kruger", "christian gotthilf kruger", "christian gottlob fauser"
"christian gottlob frege" » "christian gottlieb frege", "christian gotthilf frege", "christian gottlob frage", "christian gottlob freie"

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