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

Try widening your search to All Fields.

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• Performing a fuzzy search may retrieve terms with similar spellings: (((("a robust b. heilman book") OR ("a robust a. heilman book"))) or ("3 robert b. heilman books"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("a robust b. heilman book") OR ("a robust a. heilman book"))) OR ("3 robert b. heilman books")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"a robust b. heilman book\") OR (\"a robust a. heilman book\"))) or (\"3 robert b. heilman books\"))".
• Removing quotes may allow a broader search: (((( a robust b. heilman book ) OR ( a robust a. heilman book ))) or ( 3 robert b. heilman books )).
• Adding a wildcard symbol may retrieve word variants: (((("a robust b. heilman book") OR ("a robust a. heilman book"))) or ("3 robert b. heilman books"))*.