., Widayati.
 Kondisi Urutan Natural Pada Semigrup Reguler.
<strong>Jurnal Matematika</strong>, [S.l.], v. 3, n. 1, p. 24 - 33, july 2013.
ISSN 2655-0016.
Tersedia pada: &lt;<a href="http://103.29.196.112/index.php/jmat/article/view/7329" target="_new">http://103.29.196.112/index.php/jmat/article/view/7329</a>&gt;. Tanggal Akses: 04 mar. 2026
doi: <a href="https://doi.org/10.24843/JMAT.2013.v03.i01.p32">https://doi.org/10.24843/JMAT.2013.v03.i01.p32</a>.