Tham khảo Bộ Thủy phỉ

  1. ↑ Bartling, F. G. (1830). Ordines naturales plantarum. Göttingen. tr. 16. 
  2. ↑ Retallack, Gregory J. (1997). “Earliest Triassic origin of Isoetes and quillwort evolutionary radiation”. Journal of Paleontology 7 (3): 500–521. 
  3. ↑ Retallack, Gregory J. (2013). “Permian and Triassic greenhouse crises”. Gondwana Research 24: 90–103. doi:10.1016/j.gr.2012.03.003. 
  4. ↑ Stewart, Wilson N.; Gar W. Rothwell (1993). Paleobotany and the Evolution of Plants (ấn bản 2). Cambridge University Press. tr. 150–153. ISBN 0-521-38294-7.