Perhaps you should try some spelling variations:
"a robust _. hermann ebook" » "a robust _. german book", "_ robust _. hermann ebook"
"a robot j. heimann book" » "a robot j. german book", "_ robot j. heimann book", "a robot _. heimann book", "a robot 5. heimann book", "a robot k. heimann book"
"a robot 1. heimann book" » "a robot 1. german book", "_ robot 1. heimann book", "a robot 19. heimann book", "a robot _. heimann book", "a robot 5. heimann book"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("a robust _. hermann ebook") or ((("a robot j. heimann book") OR ("a robot 1. heimann book"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("a robust _. hermann ebook") OR ((("a robot j. heimann book") OR ("a robot 1. heimann book"))))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"a robust _. hermann ebook\") or (((\"a robot j. heimann book\") OR (\"a robot 1. heimann book\"))))*".
• Removing quotes may allow a broader search: (( a robust _. hermann ebook ) or ((( a robot j. heimann book ) OR ( a robot 1. heimann book ))))*.