↑Micheli, P. A. (1729). Nova Plantarum Genera juxta Tournefortii methodum disposita. Florence: [s.n.] p.4, plate iii
↑Boehmer, G. R. (1760). Ludwig, C. G., ed. Definitiones Generum Plantarum 3rd ed. [S.l.: s.n.] p.501
↑Schuster, Rudolf M. (1992). The Hepaticae and Anthocerotae of North America. V. Chicago: Field Museum of Natural History. pp.811–813. ISBN0-914868-20-9