Tham khảo Đới_(địa_tầng)

Tài liệu tham khảo

WikiPedia: Đới_(địa_tầng) http://www.rocksandminerals.com/geotime/geotime.ht... http://www.ucmp.berkeley.edu/help/timeform.html http://astro.wsu.edu/worthey/earth/html/md08.html http://www2.nature.nps.gov/geology/usgsnps/gtime/g... http://www.pballew.net/arithm16.html#aeon http://www.pballew.net/etyindex.html http://www.journals.cambridge.org/action/displayAb... //dx.doi.org/10.1017%2FS001675680100509X http://www.stratigraphy.org/cheu.pdf http://www.stratigraphy.org/chron.htm