olemus
aastate nummerduse süsteem
Julianuse ja Gregoriuse kalendrites,
alguspunktiga AD 1

Wiktionary:
(chronology) the secular equivalent of anno Domini and the Christian Era, the internationally recognized method of numbering years on the Gregorian calendar

ülevaateid
https://en.wikipedia.org/wiki/Common_Era

https://www.druide.com/en/reports/bc-and-ad-bce-and-ce-whats-difference

https://rationalwiki.org/wiki/Common_Era

https://www.khanacademy.org/humanities/ap-art-history/start-here-apah/brief-histories-apah/a/common-questions-about-dates

https://en.wikipedia.org/wiki/Template:Year_in_various_calendars