1. Rumiati, K. Fahmi dan B. Edison, “Analisis Kemampuan Membayar dan Kemauan Membayar Tarif Angkutan Umum Mini Bus (Superben) di Kabupaten Rokan Hulu,” Jurnal Mahasiswa Fakultas Teknik, vol. 1, no. 1, 2013.
2. Exploring the Willingness and Ability to Pay for Paratransit in Bandung, Indonesia
3. Willingness To Pay Rumah Tangga Dalam Membayar Biaya Pendidikan Menengah Unggulan di Kota Malang
4. SMA Unggul Del, "Tentang SMA Unggul Del - SMA Unggul Del," [Online]. Available: http://www.smadel.sch.id/?page_id=73. [Accessed 12 Maret 2019].
5. E. Ekanem, J. E. Okon dan U. I. Ekpoh, “Reforming Education through User Fees: Ability and Willingness to Pay for University Education in Calabar, Nigeria,” Journal of Education and Practice, vol. 3, no. 8, pp. 245-250, 2012.