Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 77. (Budapest 1985)

Kordos-Szakály, M. ; Kordos, L.: Morphotypes of Hungarian fossil Celtis (Urticales) stones

Cross sections of stony endocarps of recent and fossil Celtis species (above: outer surface, below: inner surface) : 1 = Celtis australis, recent, 2 = Celtis tournefortii, recent, 3 = Celtis occidentalis, recent, 4 = "pillow", Tarkő 16, 5 = "torpedo", Rudabánya, 6 = "macro", Rudabánya, 7 = "pill", Rudabánya, 8 = "oval", Rudabánya. — All are SEM photos, magnified 90X