Regulations under the PCT
PART D
RULES CONCERNING CHAPTER III OF THE TREATY
Rule 79
Calendar
Applicants, national Offices, receiving Offices, International Searching and Preliminary Examining Authorities, and the International Bureau, shall, for the purposes of the Treaty and the Regulations, express any date in terms of the Christian era and the Gregorian calendar, or, if they use other eras and calendars, they shall also express any date in terms of the Christian era and the Gregorian calendar.