Henning, I.D.; Collins, J.V.: 'Measurements of the semiconductor laser linewidth broadening factor', Electronics Letters, 1983, 19, (22), p. 927-929, DOI: 10.1049/el:19830633
IET Digital Library, https://digital-library.theiet.org/;jsessionid=7prvetk57jl5.x-iet-live-01content/journals/10.1049/el_19830633