Irene, D., and M. Mansur. “Analisis Faktor Kegagalan Referendum Catalunya Tahun 2006 – 2017”. Balcony, vol. 3, no. 1, Feb. 2019, pp. 59-69, https://jom.fisip.budiluhur.ac.id/index.php/balcony/article/view/46.