The Yavi Formation (Lower Cretaceous), Upper Magdalena Valley Colombia; An integrated sedimentological and palynological study.
Reference:
Prжssl,K.F. et al. (1993)
The Yavi Formation (Lower Cretaceous), Upper Magdalena Valley Colombia; An integrated sedimentological and palynological study. Neues Jahrbuch fмr Geologie und Pal¤ontologie. Abhandlungen
Vol. 188 # 2 P. 213- 240