Loeblich, A. R., Tappan, H. N., 1987: Foraminiferal genera and their classification. Van Nostrand, Reinhold Co. New York 1728 pp. Plate 39, Fig. 21: U. Triassie (Carnian), Chukotka, Russia. Holotype, x 10 (from Vyalov, 1977). courtesy of Michael Hesemann https://foraminifera.eu
