Perhaps you should try some spelling variations:
"occasional letters; occasional letter" » "occasional prayers; occasional letter", "occasional papers; occasional letter", "occasional verses; occasional verse"
"occasional writers; occasional writer" » "occasional drivers; occasional writer", "occasional writings; occasional writer", "occasional prayers; occasional writer", "occasions writtens; occasions written"
"occasional notess; occasional notes" » "occasional notices; occasional notes", "occasional poems; occasional notes", "occasion notes; occasional notes"

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