Catanzariti, Rita, and Nicola Perilli. “AGE OF THE OTTONE UNIT IN THE ZIGNAGO AREA (EXTERNAL LIGURIAN UNITS, NORTHERN APENNINES): CONSTRAINTS FROM CALCAREOUS NANNOFOSSILS”. Ofioliti, vol. 31, no. 1, Mar. 2006, pp. 11-24, doi:10.4454/ofioliti.v31i1.324.