BOUCKAERT, J. ET AL. - Biostratigraphic chart of the Famennian stage (upper Devonian) in the type localities of Belgium; a preliminary report.

- 1969. Journal of Paleontology Vol.43; 727-734, 1 fig. 2 plts. h.t. with spores, 1 plt. h.t. with stratigr.table folding-out. Orig. extract, stapled, very good.