de Paiva, J.R. and Kageyama, P.Y. 1993. New approach for rubber tree breeding for the amazon region. Pesquisa Agropecuaria Brasileira. 28, 12 (Dec. 1993), 1391–1398. DOI:https://doi.org/10.1590/S1678-3921.pab1993.v28.4012.