SINGH, Lavalesh Pratap; RAI, Adya Shakti. Visually Challenged Students’ Proficiency in the Use of Abacus. JOURNAL OF INDIAN EDUCATION, [S. l.], v. 40, n. 2, p. p.91–98, 2014. Disponível em: http://ejournals.ncert.gov.in/index.php/jie/article/view/1656. Acesso em: 6 jul. 2025.