there is a certain calendar system called the julian calendar which uses a month that measures less than 28 days. this criteria is also used in another calendar that is called what?
(AND time.calendar (JOIN (R time.month.calendar_system) (AND (JOIN time.month.calendar_system m.06jx2) (le time.month.number_of_days_in_month 28^^http://www.w3.org/2001/XMLSchema#integer))))