M. Muliani and D. Sumarsono, “CONTEXTUAL TEACHING LEARNING (CTL) APPROACH IN SPEAKING MATERIALS FOR STUDENTS’ 21ST CENTURY SKILL: DOES IT HAVE ANY EFFECT?”, J. Engl. Lang. Teach. Fak. Pendidik. Bhs. Seni Program Studi Pendidik. Bhs. Ingg. IKIP Mataram, vol. 6, no. 2, pp. 99–105, Dec. 2019.