| original |
Middle Cambrian |
|
USSR(Russian Platform) |
Umnova,N.I. et al. Acritarch assemblages from the Cambrian and Early Ordovician sediments of western and northwestern Russian Platform. (In: Palynology research in Byelorussia and other Regions of the USSR) |
1971 |
| details |
Early Cambrian |
|
Europe |
Yankauskas,T.V. On the micropalaeontological characteristic of the Middle and Upper Cambrian in the Northwest of the East-European Platform. |
1980 |
| details |
Early Cambrian |
Middle Cambrian |
USSR(Leningrad) |
Borovko,N.G. et al. The reference section of Cambrian and Ordovician boundry sediments at North-West Russian Plate (Izhora River) |
1984 |
| details |
Middle Cambrian |
|
Nd |
Fensome,R.A. et al. Acritarchs and Fossil Prasinophytes: An index to genera, species and infraspecific taxa. |
1990 |