MAJEED, R. N.; 						NASIR, A. I..
 Some Results on Semi-preopen Sets.
<strong>Ibn AL- Haitham Journal For Pure and Applied Science</strong>, [S.l.], v. 22, n. 3, aug. 2017.
ISSN 2521-3407.
Available at: &lt;<a href="http://jih.uobaghdad.edu.iq/index.php/j/article/view/1184" target="_new">http://jih.uobaghdad.edu.iq/index.php/j/article/view/1184</a>&gt;. Date accessed: 01 dec. 2019.