[The Acritarcha and stratigraphy of the Lower Middle Cambrian strata in western Latvia.] Sorokin, V.S.[Ed]. [Paleontology and stratigraphy of the Phanerozoic of Latvia and the Baltic Sea.], Zinatne, Riga., 1992: 1-179. Chapter pagination: 19-33. 31 [Zoological Record Volume 134]