VanAller Hernick, L., Landing, E., Bartowski, K.E., 2008. Earth's Oldest Liverworts--Metzgeriothallus sharonae sp. nov. from the Middle Devonian (Givetian) of Eastern New York. Review of Palaeobotany & Palynology 148, 154-162. doi:10.1016/j.revpalbo.2007.09.002