Perhaps you should try some spelling variations:
michael della » michael kelly, michael heller, michael de
della author » cells author, kelly author, wells author
michael only » michael one, michael orey, michael odell
only author » any author, cowley author

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (( michael della author ) OR ( michael only author )).
• Adding a wildcard symbol may retrieve word variants: (( michael della author ) or ( michael only author ))*.