RATNAWATI, DIAH. 2015. “THE EFFECT OF USING CO-OP CO-OP TECHNIQUE IN TEACHING WRITING NARRATIVE TEXT TO THE TENTH GRADERS OF SMAN 3 SIDOARJO”. RETAIN : Journal of Research in English Language Teaching 3 (2). https://ejournal.unesa.ac.id/index.php/retain/article/view/12391.