Yulianti, Y. “METODE TUTOR SEBAYA BERBANTUAN WHATSAPP UNTUK MENINGKATKAN HASIL UJI COBA UJIAN NASIONAL DI SMK NEGERI 1 TANJUNGPANDAN”. IDEAL MATHEDU: Indonesian Digital Journal of Mathematics and Education, Vol. 6, no. 2, Dec. 2019, pp. 691-03, http://p4tkmatematika.kemdikbud.go.id/journals/index.php/idealmathedu/article/view/57.