Renandya, W. A., Krashen, S., & Jacobs, G. M. (2018). The Potential of Series Books: How Narrow Reading Leads to Advanced L2 Proficiency. LEARN Journal: Language Education and Acquisition Research Network, 11(2), 148–154. Retrieved from https://so04.tci-thaijo.org/index.php/LEARN/article/view/161631