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 writers; occasional writer" » "occasional drivers; occasional writer", "occasional writings; occasional writer", "occasional prayers; occasional writer", "occasional notess; occasional notes", "occasions writtens; occasions written"
"occasional verses; occasional verse" » "occasional sermons; occasional verse", "occasional notes; occasional verse"

Try widening your search to All Fields.

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