Rhein, A. F. de L., Santos, D. M. M. dos and Carlin, S. D. (2011) “Nitrate reductase enzyme activity and free proline contents in sugarcane roots under water and acid stress in soil”, Semina: Ciências Agrárias, 32(4), pp. 1345–1360. doi: 10.5433/1679-0359.2011v32n4p1345.