Perhaps you should try some spelling variations:
"michael kelly author" » "michael heller author", "michael kirby author", "michael kelly anthony", "michael henry author", "michael only author"
"michael della author" » "michael heller author", "michael de author", "michael cells author", "michael wells author", "michael bellamy author"

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"michael kelly author\") OR (\"michael della author\"))".
• Removing quotes may allow a broader search: (( michael kelly author ) OR ( michael della author )).
• Adding a wildcard symbol may retrieve word variants: (("michael kelly author") OR ("michael della author"))*.