S. ARULRAJ AND G.PERUMAL*. Threshold Typology and Its Characteristics. Indian Journal of Extension Education, India, v. 27, n. 3-4, p. 1–6, 1991. DOI: 10.48165/. Disponível em: https://epubs.icar.org.in/index.php/IJEE/article/view/160544. Acesso em: 24 oct. 2025.