(1)
W.A. van Wamel; A.J. Bons; R.C.M.W. Franssen; W. van Lingen; W. Postuma; A.C.A. van Zutphen. A Structural Geologic Traverse through the Northern Apennines from Rapallo to Bettola (N. Italy) . njg 1985, 181-197.