Reekie, L.; Jauncey, I.M.; Poole, S.B.; Payne, D.N.: 'Diode-laser-pumped operation of an Er<sup>3+</sup>-doped single-mode fibre laser', Electronics Letters, 1987, 23, (20), p. 1076-1078, DOI: 10.1049/el:19870752
IET Digital Library, https://digital-library.theiet.org/;jsessionid=1916aa2uqrme3.x-iet-live-01content/journals/10.1049/el_19870752