Perhaps you should try some spelling variations:
"a robust e. hellman book" » "a robust e. hellman joel", "a robust e. german book", "_ robust e. hellman book", "a robust _. hellman book", "a robust a. hellman book", "a robust end. hellman book"
"a robert j. heitmann book" » "3 robert j. heitmann book", "dr robert j. heitmann book", "a robert _. heitmann book", "a robert e. heitmann book"
"a robot j. heitmann book" » "_ robot j. heitmann book", "a robot _. heitmann book", "a robot 1. heitmann book", "a robot 5. heitmann 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 j. heitmann book") OR ("a robot j. heitmann book"))) or ("a robust e. hellman book"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("a robert j. heitmann book") OR ("a robot j. heitmann book"))) OR ("a robust e. hellman book")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"a robert j. heitmann book\") OR (\"a robot j. heitmann book\"))) or (\"a robust e. hellman book\"))".
• Removing quotes may allow a broader search: (((( a robert j. heitmann book ) OR ( a robot j. heitmann book ))) or ( a robust e. hellman book )).
• Adding a wildcard symbol may retrieve word variants: (((("a robert j. heitmann book") OR ("a robot j. heitmann book"))) or ("a robust e. hellman book"))*.