D’ARPA, C. and MELÉNDEZ, G. (2004) “OXFORDIAN BIOSTRATIGRAPHY AND AMMONITE ASSOCIATIONS FROM WEST SICILY: BIOSTRATIGRAPHIC SUCCESSION OF GENUS <em>GREGORYCERAS</em> AND CORRELATION WITH TETHYAN PERISPHINCTID SCALE”, RIVISTA ITALIANA DI PALEONTOLOGIA E STRATIGRAFIA , 110(1). doi: 10.13130/2039-4942/6296.