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

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"christian gottlob frege\") OR (\"christian gotthilf frege\"))*".
• Removing quotes may allow a broader search: (( christian gottlob frege ) OR ( christian gotthilf frege ))*.