Landing, E.; Westrop, S.R.; Adrain, J.M. The Lawsonian Stage - the Eoconodontus notchpeakensis FAD and HERB carbon isotope excursion define a globally correlatable terminal Cambrian stage. Bulletin of Geosciences. 19 September 2011: 621–640. doi:10.3140/bull.geosci.1251.