Perhaps you should try some spelling variations:
jaef robert » jaef roberto, janett robert, lahey robert
heilmann » heinemann, hermann, heymann
heitmann » heinemann, hermann, hartmann
heitmannn » heinemannn, hermannn, hartmannn
hellman » helpman
heimann » hermann, heinemann
book* » books*, ebook*

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: jaef robert _. (((heilmann OR heitmann) or hellman) or (heimann or heitmannn)) book~.
• If you are trying to use Boolean operators, they must be ALL CAPS: jaef robert _. (((heilmann OR heitmann) OR hellman) OR (heimann OR heitmannn)) book*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "jaef robert _. (((heilmann OR heitmann) or hellman) or (heimann or heitmannn)) book*".