F. E. V. Santos, M. V. W. Caldeira, and S. H. Kunz, “Quality of seedlings of <em>Parapiptadenia rigida</em> (Benth.) Brenan produced in different substrates with sewage sludge and rice hulls”, Ecol. Nutr. Flor., vol. 1, no. 2, pp. 55–62, Jul. 2014.