Zuykov, M. A., Harper, D. A. T. 2007.
Platystrophia (Orthida) and new related Ordovician and Early Silurian brachiopod genera.Estonian Journal of Earth Sciences56,
1,11-34.
Oraspõld, A. L. 1956.
New brachiopods from the Jõhvi, Keila and Vasalemma stages.ENSV TA Geoloogia Instituudi uurimusedI,
41-67.