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