Perhaps you should try some spelling variations:
"a robert b. heilman books" » "a robert b. german books", "3 robert b. heilman books", "dr robert b. heilman books", "a robot b. heilman books", "a robert _. heilman books", "a robert e. heilman books", "a robert j. heilman books"
"a robust b. german book" » "a robust b. german books", "a robust b. german food", "_ robust b. german book", "a robust _. german book", "a robust a. german book", "a robust job. german book"
"a robust b. heilman book" » "_ robust b. heilman book", "a robust _. heilman book", "a robust a. heilman book", "a robust job. 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 robust b. heilman book") OR ("a robust b. german book"))) or ("a 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 b. german book"))) OR ("a 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 b. german book\"))) or (\"a robert b. heilman books\"))".
• Removing quotes may allow a broader search: (((( a robust b. heilman book ) OR ( a robust b. german book ))) or ( a robert b. heilman books )).
• Adding a wildcard symbol may retrieve word variants: (((("a robust b. heilman book") OR ("a robust b. german book"))) or ("a robert b. heilman books"))*.