Palynological correlation of major Pennsylvanian, (Middle and Upper Carboniferous), chronostratigraphic boundaries in Illinois and other Acoal Basins.
Reference:
Peppers,R.A. (1996)
Palynological correlation of major Pennsylvanian, (Middle and Upper Carboniferous), chronostratigraphic boundaries in Illinois and other Acoal Basins. Geological Society of America, Memoir
# 188 P. 1- 115