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