Hydrozoa Owen, 1843

Selection of related publications
Mierzejewski, P. 1986. Ultrastructure, taxonomy and affinities of some Ordovician and Silurian organic microfossils. Palaeontologia Polonica 47, 129-220.
Obut, A. M. 1960. Correlation of some parts of Estonian Ordovician and Silurian deposits according to graptolites. Trudy Instituta geologii AN ESSR 5, 143-157. Eesti NSV Teaduste Akadeemia Geoloogia Instituudi Uurimused V, pp. 143-157.
Öpik, A. 1928. Beiträge zur Kenntnis der Kukruse-(C2-C3-)Stufe in Eesti. III. Tartu Ülikooli Geoloogia Instituudi Toimetused 12, 1-42.