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