Perhaps you should try some spelling variations:
"a robust a. german book" » "a robust a. german books", "a robust a. german food", "_ robust a. german book", "a robust _. german book", "a robust cat. german book", "a robust lca. 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 robert _. heilman ebook" » "3 robert _. heilman ebook", "dr robert _. heilman ebook", "a robot _. heilman 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 a. german book") or ("a robust end. german book"))) or ("a robert _. heilman ebook"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("a robust a. german book") OR ("a robust end. german book"))) OR ("a robert _. heilman ebook")).
• Removing quotes may allow a broader search: (((( a robust a. german book ) or ( a robust end. german book ))) or ( a robert _. heilman ebook )).
• Adding a wildcard symbol may retrieve word variants: (((("a robust a. german book") or ("a robust end. german book"))) or ("a robert _. heilman ebook"))*.