Allan, Dennis: 'IEE Power Division: Chairman's address. Power transformers—the second century', Power Engineering Journal, 1991, 5, (1), p. 5-14, DOI: 10.1049/pe:19910004
IET Digital Library, https://digital-library.theiet.org/;jsessionid=8h1qrqgfodlkl.x-iet-live-01content/journals/10.1049/pe_19910004