Perhaps you should try some spelling variations:
"fechner gustav friedrich" » "fechner justus friedrich", "fechner kuster friedrich", "fechner august friedrich", "fester gustav friedrich", "pacher gustav friedrich", "werner gustav friedrich"
"fechner gustav erich" » "fester gustav erich", "pacher gustav erich", "werner gustav erich", "fechner gustavi erici", "fechner gustav heinrich", "fechner gustav brink"

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: "((\"fechner gustav erich\") OR (\"fechner gustav friedrich\"))".
• Removing quotes may allow a broader search: (( fechner gustav erich ) OR ( fechner gustav friedrich )).
• Adding a wildcard symbol may retrieve word variants: (("fechner gustav erich") OR ("fechner gustav friedrich"))*.