Aryanti, Nurul, and Emzir Emzir. “The Use of Visualization With Pictures and Concept Mapping to Improve English Vocabulary Mastery of Pre-School Children”. IJLECR (International Journal of Language Education and Cultural Review), vol. 2, no. 2, Dec. 2016, pp. 48-59, doi:10.21009/IJLECR.022.017.