SUNDAY, Yomi et al.
 Development and Assessment of Upper Basic Students’ Conceptual Understanding of Mathematics Knowledge Using Two-Tier Diagnostic Test in Kogi State, Nigeria.
<strong>NIU Journal of Educational Research</strong>, [S.l.], v. 12, n. 2, p. 47-62, june 2026.
ISSN 3007-1852.
Available at: &lt;<a href="https://www.niujournals.ac.ug/ojs/index.php/NIUJED/article/view/2518" target="_new">https://www.niujournals.ac.ug/ojs/index.php/NIUJED/article/view/2518</a>&gt;. Date accessed: 24 june 2026.
doi: <a href="https://doi.org/10.58709/niujed.v12i2.2518">https://doi.org/10.58709/niujed.v12i2.2518</a>.