GABRIEL, Erwin.
 --.
<strong>Philippine Engineering Journal</strong>, [S.l.], v. 38, n. 1, june 2017.
ISSN 2718-9287.
Available at: &lt;<a href="https://journals.upd.edu.ph/index.php/pej/article/view/5671" target="_new">https://journals.upd.edu.ph/index.php/pej/article/view/5671</a>&gt;. Date accessed: 06 sep. 2025.