Perhaps you should try some spelling variations:
occasional letters » occasional writer, occasional papers
occasional prayers » occasional poems, occasional writer
occasional notices » occasionally noticed, occasional offices, occasional copies
occasional letter » occasional writer, occasional verse
occasional notess » occasional poems, occasion notes, occasional distress

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