Robuta

https://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetail&idt=GEODEBRGM6820001929 BIOSTRATIGRAPHIC RANGE OF CONODONTS IN THE TREMADOCIAN STAGE (ORDOVICIAN) OF THE LENINGRAD OBLAST. in theleningrad oblastbiostratigraphicrangeconodonts