K. M.  Pryer and Hearn, D. J., ?Evolution of Leaf Form in Marsileaceous Ferns: Evidence for Heterochrony?, Evolution, vol. 63, no. 2, 2009.

N. S.  Nagalingum, Nowak, M. D., and Pryer, K. M., ?Assessing phylogenetic relationships in extant heterosporous ferns (Salviniales), with a focus on Pilularia and Salvinia?, Botanical Journal of the Linnean Society, vol. 157, no. 4, 2008.