Perhaps you should try some spelling variations:
"georg vilhelm friedrich hegel" » "georg michael friedrich hegel", "georg eichen friedrich hegel", "georg halm friedrich hegel", "georg wilhelm friedrich hegel", "georg helm friedrich hegel", "berg wilhelm friedrich hegel"
"gerke wilhelm friedrich engels" » "gehrke wilhelm friedrich engels", "werk wilhelm friedrich engels", "menke wilhelm friedrich engels"

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: (("georg vilhelm friedrich hegel") OR ("gerke wilhelm friedrich engels")).
• Removing quotes may allow a broader search: (( georg vilhelm friedrich hegel ) or ( gerke wilhelm friedrich engels )).
• Adding a wildcard symbol may retrieve word variants: (("georg vilhelm friedrich hegel") or ("gerke wilhelm friedrich engels"))*.