[3] Jahwan Koo, Internet QoS Differentiation (English Edition), VDM Verlag Dr. Mueller e.K., 2008 (ISBN: 978-3-639-04001-2).
[2] Jinwook Chung, Seongjin Ahn, Hyuncheol Kim, and Jahwan Koo, Understanding Information and Communication Technology (Korean Edition), Life & Books Press, 2005 (ISBN: 89-7050-424-9).
[1] Jinwook Chung and Jahwan Koo, Network Principles and Practices (including Lab Activity Movies) (Korean Edition), Life & Books Press, 2004 (ISBN: 89-7050-386-2).