Gold, M.P.; Hartog, A.H.: 'Determination of structural parameter variations in single-mode optical fibres by time-domain reflectometry', Electronics Letters, 1982, 18, (12), p. 489-490, DOI: 10.1049/el:19820332
IET Digital Library, https://digital-library.theiet.org/;jsessionid=4prcb8qnc9vtt.x-iet-live-01content/journals/10.1049/el_19820332