Authors Year Title
Becker, Jansen & Plodowski 2004 Devonian litho- and biostratigraphy of the Dra Valley area - an overview.
[Becker,R.T., Jansen,U., Plodowski,G., Schindler,E., Vogel,O. & Weddige,K.]
Devonian Neritic-Pelagic correlation and events in the Dra Valley (Western Anti-Atlas, Morocco,  A. El Hassani, ed., Docum.Inst.Scient., 19: 3-18, 5 fig., Rabat.