http://www.monitorapp.co.kr/security_threat_trend/voip_st.html
http://visu4l.tistory.com/330
http://www.youtube.com/watch?v=z85LlYYAUOc
http://www.lovedial.co.kr/way-board/way-board.php?db=bbs03&j=v&number=1850&pg=1&cv=&sf=&sd=&sw=&ps=3006&pe=6
http://www.lovedial.co.kr/way-board/way-board.php?db=bbs03&j=v&number=2174&pg=1&cv=&sf=&sd=&sw=&ps=3006&pe=6
http://www.lovedial.co.kr/way-board/way-board.php?db=bbs03&j=v&number=2175&pg=1&cv=&sf=&sd=&sw=&ps=3006&pe=6
http://www.lovedial.co.kr/way-board/way-board.php?db=bbs03&j=v&number=2176&pg=1&cv=&sf=&sd=&sw=&ps=3006&pe=6http://www.lovedial.co.kr/way-board/way-board.php?db=bbs03&j=v&number=2583&pg=1&cv=&sf=&sd=&sw=&ps=3006&pe=6
http://www.lovedial.co.kr/way-board/way-board.php?db=bbs03&j=v&number=1827&pg=1&cv=&sf=&sd=&sw=&ps=3006&pe=6
https://www.google.co.kr/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&sqi=2&ved=0CGUQFjAG&url=http%3A%2F%2Feiec.kdi.re.kr%2Fcommon%2Fbddown.jsp%3Ffidx%3D1925&ei=yz_zUrybLYfykQXjlYDwCA&usg=AFQjCNEqvqcpKiIxBY5BFabKpKlNAZI6Ew&sig2=B7KkCg8vIVOHfIE1923gRg&bvm=bv.60799247,d.dGI&cad=rjt
http://www.mediaus.co.kr/news/articleView.html?idxno=29639
http://www.journalist.or.kr/bbs/list.html?table=bbs_12&idxno=18708