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