Estil, Jimboy P., et al. “Design and Development of Solar-Powered Safety Motorcycle Helmet With Voice Warning System: Vol.3, No.1A”. Ascendens Asia Singapore – Bestlink College of the Philippines Journal of Multidisciplinary Research, vol. 3, no. 1A, Apr. 2024, https://ojs.aaresearchindex.com/index.php/aasgbcpjmra/article/view/12764.