Perhaps you should try some spelling variations:
"a robust e. german book" » "a robust e. german books", "a robust e. german food", "_ robust e. german book", "a robust _. german book", "a robust a. german book", "a robust l1. german book"
"a robust end. german book" » "a robust end. german books", "a robust end. german food", "a robust read. german book", "a robust bound. german book", "_ robust end. german book", "a robust _nd. german book", "a robust and. german book", "a robust l1nd. german book"
"a robert j. heilman ebook" » "3 robert j. heilman ebook", "dr robert j. heilman ebook", "a robot j. heilman ebook", "a robert _. heilman ebook", "a robert e. heilman ebook", "a robert j. heilmann ebook", "a robert j. hellman ebook", "a robert j. helman ebook"

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