Perhaps you should try some spelling variations:
"authors, german / 18th century / correspondence" » "authors, germany / 18th century / correspondence"
"author, german / 18th century / corresponding" » "author, germany / 18th century / corresponding"

Try widening your search to All Fields.

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: (("authors, german / 18th century / correspondence") OR ("author, german / 18th century / corresponding")).
• Removing quotes may allow a broader search: (( authors, german / 18th century / correspondence ) or ( author, german / 18th century / corresponding )).
• Adding a wildcard symbol may retrieve word variants: (("authors, german / 18th century / correspondence") or ("author, german / 18th century / corresponding"))*.