	Authors	Year	Title
	Bisat	1928	The Carboniferous goniatite zones of England and their continental equivalents. Congrès de Stratigraphie Carbonifère, Heerlen 1927, C.R.B.: 117-133, pl.6, 6a; Liège.
	Moore	1936	The Bowland Shales from Pendle to Dinckley. Journal of the Manchester Geological Association,: 167-192, fig.1-3, pl.1-3; Manchester.