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