See URL for details : https://www.researchsea.com/html/article.php/aid/11453/cid/1/research/science/electronics_and_telecommunications_research_institute_etri_/ultra-high_speed_wi-fi_developed_for_seoul___s_subway_trains__.html

Source : Asia Research News

See URL for details : http://www.yourindustrynews.com/seoul's+subway+trains+equipped+with+ultra-fast+internet_147615.html

Source : Your Industry News

See URL for details : https://article.wn.com/view/WNAT2ce406cdbc92fe7f4ec7ac30ff38bce4/

Source : World News