De Gracia, Erwen, et al. “Effectiveness of Vacuum Eraser for Chalk Dust Removal”. Ascendens Asia Singapore – Bestlink College of the Philippines Journal of Multidisciplinary Research, vol. 2, no. 1, Apr. 2020, https://ojs.aaresearchindex.com/index.php/aasgbcpjmra/article/view/1753.