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

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• Performing a fuzzy search may retrieve terms with similar spellings: (("a robust b. heilman book") or ((("a robert b. hellman book") OR ("a robert j. hellman book"))))~.
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• 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 j. hellman book\"))))".
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• Adding a wildcard symbol may retrieve word variants: (("a robust b. heilman book") or ((("a robert b. hellman book") OR ("a robert j. hellman book"))))*.