Set a reoccurring reminder for every 28 days, starting today; label it as """"period time.
[IN:CREATE_REMINDER Set a reoccurring reminder [SL:RECURRING_DATE_TIME [IN:GET_RECURRING_DATE_TIME for [SL:FREQUENCY every 28 days ] ] ] , [SL:DATE_TIME starting today ] ; label it as " " " " [SL:TODO period time ] . ]