Perhaps you should try some spelling variations:
"a robert b. hellman book" » "a robert b. german book", "3 robert b. hellman book", "dr robert b. hellman book", "a robot b. hellman book", "a robert _. hellman book", "a robert e. hellman book", "a robert j. hellman book"
"a robust b. heilman book" » "a robust b. german book", "_ robust b. heilman book", "a robust _. heilman book", "a robust a. heilman book", "a robust job. heilman book"
"a robert b. hellman joel" » "3 robert b. hellman joel", "dr robert b. hellman joel", "a robot b. hellman joel", "a robert _. hellman joel", "a robert e. hellman joel", "a robert j. hellman joel"

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