CHIRANEE VANICHKUL; AMNAT SUWANARIT; PREEDA PARKPIAN. Copper Critical Levels and Supplying Powers of Takhli, Loei, and Khorat Soil Series for Corn Production. Agriculture and Natural Resources, Bangkok, Thailand, v. 27, n. 1, p. 44–55, 1993. Disponível em: https://li01.tci-thaijo.org/index.php/anres/article/view/241550. Acesso em: 17 sep. 2026.