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