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