Loeblich, A. R., Tappan, H. N., 1987: Foraminiferal genera and their classification. Van Nostrand, Reinhold Co. New York 1728 pp. Plate 236, Fig. 8: L. Carboniferous (L. Visean), Dnieper-Donets Basin. Median section, x 55 (from Vdovenko, 1967). courtesy of Michael Hesemann https://foraminifera.eu