Haag, Henrique Paulo, Herminia E. P. Martinez, and Mário L.T. Moraes. 1991. “Micronutrients in Caribean Pine. II. Boron and Cooper Corresponding Sufficiency and Deficiency Internal Levels”. Pesquisa Agropecuaria Brasileira 26 (3):419-30. https://doi.org/10.1590/S1678-3921.pab1991.v26.3358.