Age calibration of the Lower Ordovician Fezouata Lagerstätte (Morocco) - Lefebvre, Bertrand; Lehnert, Oliver; Gutiérrez-Marco, Juan Carlos; Martin, Emanuel L. O.; Nowak, Hendrik; Akodad, Mustapha; El Hariri, Kadija; Servais, Thomas (Lethaia, 2017)