| original |
Middle Ordovician |
|
Sweden |
Kjellstrжm,G. Middle Ordovician microplankton from the Grotlingbo borehole No.1 in Gotland, Sweden. |
1971 |
| details |
Ordovician |
|
Sweden |
Eisenack,A. et al. Catalog of fossil dinoflagellates, hystrichospheres and related microfossils. Acritarchs. |
1973 |
| details |
Llanvirnian |
Llandeilian |
Nd |
Diez,M.D.C.R. et al. Range chart of selected Lower Paleozoic acritarch Taxa. |
1974 |
| details |
Llandeilian |
|
Poland |
Gгrka,H. The Middle Ordovician acritarchs of Olsztyn IG2, (Poland). |
1979 |
| details |
Middle Ordovician |
|
Nd |
Fensome,R.A. et al. Acritarchs and Fossil Prasinophytes: An index to genera, species and infraspecific taxa. |
1990 |
| details |
Early Ordovician |
|
Sweden |
Playford,G. et al. Ordovician acritarch genera Peteinosphaeridium, Liliosphaeridium and Cycloposphaeridium: Morphology, taxonomy, biostratigraphy and palaeogeographic significance |
1995 |