| original |
Early Ordovician |
Middle Ordovician |
USSR(Pre-Baltic) |
Timofeev,B.V. Ancient flora of the Prebaltic Region and its stratigraphic significance |
1959 |
| details |
Early Ordovician |
Middle Ordovician |
USSR(Pre-Baltic) |
Downie,C. et al. On the interpretation and status of some Hystrichosphere genera. |
1963 |
| details |
Early Ordovician |
Middle Ordovician |
USSR(Pre-Baltic) |
Downie,C. et al. Bibliography and index of fossil dinoflagellates and acritarchs. |
1965 |
| details |
Ordovician |
|
Nd |
Fensome,R.A. et al. Acritarchs and Fossil Prasinophytes: An index to genera, species and infraspecific taxa. |
1990 |