JACKS, Lloyd P. Development And Use Of Subject Matter Materials For Vocational Education In Agriculture. Journal of Agricultural Education, [S. l.], v. 9, n. 1, p. 9–14, 1968. DOI: 10.5032/jaatea.1968.01009. Disponível em: https://jae-online.org/index.php/jae/article/view/2175. Acesso em: 28 jun. 2026.