Loeblich, A. R., Tappan, H. N., 1987: Foraminiferal genera and their classification. Van Nostrand, Reinhold Co. New York 1728 pp. Plate 214, Figs. 2-4: N. Kharaulakh; 2, U. Visean, horizontal section, x 100; 3, U. Tournaisian, axial section, x 70; 4, M. Visean, axial section, x 100 (from Bogush and Yuferev, 1966). courtesy of Michael Hesemann https://foraminifera.eu
