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