| original |
Middle Ordovician |
|
Sweden |
Kjellstrжm,G. Ordovician microplankton (baltisphaerids) 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 |
Caradocian |
Nd |
Diez,M.D.C.R. et al. Range chart of selected Lower Paleozoic acritarch Taxa. |
1974 |
| details |
Middle Ordovician |
|
Nd |
Fensome,R.A. et al. Acritarchs and Fossil Prasinophytes: An index to genera, species and infraspecific taxa. |
1990 |