Nitrogen isotopes in kukersite and black shale implying Ordovician-Silurian seawater redox conditionsKiipli, Enli; Kiipli, TarmoOil shale2013 / p. 60-75 : ill https://artiklid.elnet.ee/record=b2604253*est https://doi.org/10.3176/oil.2013.1.06 Journal metrics at Scopus Article at Scopus Journal metrics at WOS Article at WOS