PERILLI, NICOLA, and LUIS VICTOR DUARTE. 2006. “TOARCIAN NANNOBIOHORIZONS FROM LUSITANIAN BASIN (PORTUGAL)AND THEIR CALIBRATION AGAINST AMMONITE ZONES”. RIVISTA ITALIANA DI PALEONTOLOGIA E STRATIGRAFIA 112 (3). https://doi.org/10.13130/2039-4942/6350.