Winanto, Asis Riat, and Khusnatul Zulva Wafirotin. “Profil Sektor Informal Di Kabupaten Ponorogo”. Al Tijarah 2, no. 1 (June 30, 2016): 53–68. Accessed July 3, 2024. https://ejournal.unida.gontor.ac.id/index.php/altijarah/article/view/663.