Monteiro, Juliana Geseíra, et al. “Growth and Proline Content in Pigeon Pea Seedlings Subjected to Osmotic Stress and to Exogenous Putrescine”. Pesquisa Agropecuaria Brasileira, vol. 49, no. 1, Apr. 2014, pp. 18-25, doi:10.1590/S1678-3921.pab2014.v49.14671.