1 1 0 http://purl.dataone.org/odo/ECSO_00000668 D14C 'D14C' SubClassOf 'radioactive carbon isotope ratio' 'D14C' SubClassOf http://purl.dataone.org/odo/ECSO_00003112 http://purl.dataone.org/odo/ECSO_00003112 d14C 'd14C' SubClassOf 'carbon isotope ratio'