Use the syntax {{Period start error|period name}}
{{Period start error|Fortunian}}
produces:
± 0.2
References are provided by the template {{Period start ref}}.
As of January 2023[update] data is accurate to the International Chronostratigraphic Chart: Cohen, K.M.; Finney, S.C.; Gibbard, P.L.; Fan, J.-X. (2013-09-01). "The ICS International Chronostratigraphic Chart". Episodes. 36 (3) (updated ed.): 199–204. doi:10.18814/epiiugs/2013/v36i3/002. ISSN 0705-3797. The current version can be found at https://stratigraphy.org/chart.
This list is incomplete. You may help by expanding it