J.S. Choi, H.S. Kim, M.S. Kong, SJ. Lee, U.R. Son, May 2014, A Study on Analysis Travel
Path Return Current Harmonics Between KTX SanChun and TI21 AF Track Circuit in Signalling
Equipment, Spring Conference of the Korean Society for Railway, Vol. pp. 1, No. 588-1,
pp. 590