L. Q. Matias, A. Soares, and V. L. Scatena, “ANATOMY OF ECHINODORUS (ALISMATACEAE) SCAPES FROM NORTHEASTERN BRAZIL AS APPLIED TO TAXONOMY”, Edinburgh J. Bot., vol. 65, no. 1, pp. 11–21, Mar. 2008, doi: 10.1017/S0960428608004794.