Perhaps you should try some spelling variations:
"a robust e. hellman book" » "a robust e. hellman joel", "_ robust e. hellman book", "a robust _. hellman book", "a robert e. hellman book"
"a robert _. heitmann book" » "gal robert _. heitmann book", "a robert _. heimann book", "a robert _. heinemann book", "a robert _. hermann book"
"a robert j. heilman book" » "gal robert j. heilman book", "a robert e. heilman book", "a robert j. heilmann 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 _. heitmann book") or ("a robert j. heilman book"))) or ("a robust e. hellman book"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("a robert _. heitmann book") OR ("a robert j. heilman book"))) OR ("a robust e. hellman book")).
• Removing quotes may allow a broader search: (((( a robert _. heitmann book ) or ( a robert j. heilman book ))) or ( a robust e. hellman book )).
• Adding a wildcard symbol may retrieve word variants: (((("a robert _. heitmann book") or ("a robert j. heilman book"))) or ("a robust e. hellman book"))*.