Utomo, Singgih. “Analisis Yuridis Jual-Beli Online Buku Elektronik (E-Book) (E-Commerce) Dari Persepektif Hukum Perdata Indonesia”. MASILE, vol. 2, no. 2, Nov. 2021, https://jurnal.ipeba.ac.id/index.php/masile/article/view/36.