Perhaps you should try some spelling variations:
"a robust e. hellman book" » "a robust e. hellman joel", "a robust e. german book", "_ robust e. hellman book", "a robust _. hellman book", "a robust a. hellman book", "a robust end. hellman book"
"a robert e. heilman book" » "a robert e. german book", "3 robert e. heilman book", "dr robert e. heilman book", "a robot e. heilman book", "a robert _. heilman book", "a robert j. heilman book"
"a robust e. heilman book" » "a robust e. german book", "_ robust e. heilman book", "a robust _. heilman book", "a robust a. heilman book", "a robust end. heilman 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 robert e. heilman book") or ((("a robust e. heilman book") OR ("a robust e. hellman book"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("a robert e. heilman book") OR ((("a robust e. heilman book") OR ("a robust e. hellman book"))))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"a robert e. heilman book\") or (((\"a robust e. heilman book\") OR (\"a robust e. hellman book\"))))*".
• Removing quotes may allow a broader search: (( a robert e. heilman book ) or ((( a robust e. heilman book ) OR ( a robust e. hellman book ))))*.