Hazard, Benjamin H. (August 1973). "The Creation of the Korean Navy During the Koryŏ Period"(PDF). Transactions of the Royal Asiatic Society Korea Branch. XLVIII: 14. Archived from the original(PDF) on 2016-08-29. Retrieved 2019-09-03 – via Royal Asiatic Society-Korea Branch.
snu.ac.kr
seer.snu.ac.kr
Seoul National University-College of Humanities-Department of History (2005-04-30). "History of Science in Korea". Vestige of Scientific work in Korea. Seoul National University. Retrieved 2006-07-27.
Korean Broadcasting System-News department (2005-04-30). "Science in Korea". Countdown Begins for Launch of South Korea’s Space Rocket. Korean Broadcasting System. Retrieved 2006-07-27.
web.archive.org
Hazard, Benjamin H. (August 1973). "The Creation of the Korean Navy During the Koryŏ Period"(PDF). Transactions of the Royal Asiatic Society Korea Branch. XLVIII: 14. Archived from the original(PDF) on 2016-08-29. Retrieved 2019-09-03 – via Royal Asiatic Society-Korea Branch.