Muttaqi, Uzlifa Khanifatul. “Desaign of Converter Hijri Calendar to Ad Calendar for Determaning Islamic Great Days Using Matlab”. Journal of Natural Sciences and Mathematics Research, vol. 2, no. 1, Aug. 2017, pp. 109-16, https://journal.walisongo.ac.id/index.php/JNSMR/article/view/1643.