Perhaps you should try some spelling variations:
"occasional letters; occasional letter" » "occasional notes; occasional letter", "occasional prayers; occasional letter", "occasional papers; occasional letter", "occasional notess; occasional notes"
"occasional writer; occasional letter" » "occasional writer; occasional notes", "occasional notes; occasional letter", "occasions written; occasional letter"
"occasional verses; occasional verse" » "occasional sermons; occasional verse", "occasional notes; occasional verse"

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: (((("occasional letters; occasional letter") OR ("occasional writer; occasional letter"))) OR ("occasional verses; occasional verse")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"occasional letters; occasional letter\") OR (\"occasional writer; occasional letter\"))) or (\"occasional verses; occasional verse\"))".
• Removing quotes may allow a broader search: (((( occasional letters; occasional letter ) OR ( occasional writer; occasional letter ))) or ( occasional verses; occasional verse )).
• Adding a wildcard symbol may retrieve word variants: (((("occasional letters; occasional letter") OR ("occasional writer; occasional letter"))) or ("occasional verses; occasional verse"))*.