Ruschel, A.P. 2014. Seasonal effect on growth and simbiotic nitrogen fixation of different <i>Azolla</i> species. Pesquisa Agropecuaria Brasileira. 22, 6 (Apr. 2014), 559–565. DOI:https://doi.org/10.1590/S1678-3921.pab1987.v22.14390.