The Barremian-Aptian boundary in the Poggio le Guaine core (central Italy): evidence for magnetic polarity Chron M0r and oceanic anoxic event 1a - Savian, Jairo F; Trindade, Ricardo Ivan Ferreira da; Janikian, Liliane; Jovane, Luigi; Almeida, Renato Paes de; Coccioni, Rodolfo; Frontalini, Fabrizio; Sideri, Marianna; Figueiredo, Milene; Tedeschi, Leonardo R.; Jenkyns, Hugh C (The stratigraphic record of Gubbio: integrated stratigraphy of the late Cretaceous-Paleogene Umbria-Marche Pelagic Basin, 2016)