Phosphatic microfossils from the Ordovician of the United States / Matthew H. Nitecki --, Raymond C. Gutschick --, John E. Repetski --.

v.35:no.1(1975)

Arctoryctes and some other Chadronian vertebrate microfossils from Nebraska / [by] William D. Turnbull -- and Charles A. Reed --.

v.14:no.3(1960)