Perhaps you should try some spelling variations:
"a robust j. heilman book" » "a robust j. german book", "_ robust j. heilman book", "a robust _. heilman book", "a robust job. heilman book", "a robust l1. heilman book"
"a robust a. heilman book" » "a robust a. german book", "_ robust a. heilman book", "a robust _. heilman book", "a robust cat. heilman book", "a robust lca. heilman book"
"_ robot b. heimann ebook" » "_ root b. heimann ebook", "_ robert b. heimann ebook", "_ robust b. heimann ebook", "_ robot _. heimann ebook", "_ robot 1. heimann ebook", "_ robot 5. heimann ebook"

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