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

Try widening your search to All Fields.

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 _. german book"))~.
• 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 _. german book")).
• Removing quotes may allow a broader search: (((( a robert e. heilman book ) or ( a robert j. heilman book ))) or ( a robust _. german book )).
• Adding a wildcard symbol may retrieve word variants: (((("a robert e. heilman book") or ("a robert j. heilman book"))) or ("a robust _. german book"))*.