Perhaps you should try some spelling variations:
"a robot b. heilman book" » "a robot b. german book", "_ robot b. heilman book", "a robot 1. heilman book", "a robot 5. heilman book", "a robot k. heilman book"
"a robot _. heilman book" » "a robot _. german book", "_ robot _. heilman book"
"a robust b. heilman ebook" » "_ robust b. heilman ebook", "a robust _. heilman ebook", "a robust a. heilman ebook", "a robust job. heilman ebook"

Try widening your search to All Fields.

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 b. heilman ebook") or ((("a robot b. heilman book") OR ("a robot _. heilman book"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("a robust b. heilman ebook") OR ((("a robot b. heilman book") OR ("a robot _. heilman book")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"a robust b. heilman ebook\") or (((\"a robot b. heilman book\") OR (\"a robot _. heilman book\"))))".
• Removing quotes may allow a broader search: (( a robust b. heilman ebook ) or ((( a robot b. heilman book ) OR ( a robot _. heilman book )))).
• Adding a wildcard symbol may retrieve word variants: (("a robust b. heilman ebook") or ((("a robot b. heilman book") OR ("a robot _. heilman book"))))*.