Z. Auliya Faculty of Mathematics and Natural Sciences (FMIPA), Institut Teknologi Bandung, Jalan Ganesha No. 10, Bandung 40132, Indonesia Indonesia
R. Kurniadi Faculty of Mathematics and Natural Sciences (FMIPA), Institut Teknologi Bandung, Jalan Ganesha No. 10, Bandung 40132, Indonesia Indonesia
D. Irwanto Faculty of Mathematics and Natural Sciences (FMIPA), Institut Teknologi Bandung, Jalan Ganesha No. 10, Bandung 40132, Indonesia Indonesia