• http://www.stratigraphy.org/index.php/ics-chart-timescale
• http://resource.geosciml.org/
• https://link.springer.com/article/10.1007%2Fs12145-014-0170-6
• https://en.wikipedia.org/wiki/Geologic_time_scale#Naming_of_geologic_periods,_eras_and_epochs
• http://vocabs.ands.org.au/repository/api/lda/csiro/international-chronostratigraphic-chart/2017/resource.html?uri=http://resource.geosciml.org/classifier/ics/ischart/BaseHoloceneSP

etc