Souza, E.H. de et al. (2014) “Morphological and physiological characterization of diploid and tretraploid forms of Trifolium riograndense in comparison with Trifolium repens and Trifolium polymorphum”, Pesquisa Agropecuaria Brasileira, 23(6), pp. 599–607. doi:10.1590/S1678-3921.pab1988.v23.13931.