Gilbert, B.: 'Translinear circuits: a proposed classification', Electronics Letters, 1975, 11, (1), p. 14-16, DOI: 10.1049/el:19750011
IET Digital Library, https://digital-library.theiet.org/;jsessionid=2hvopoi4v7ub1.x-iet-live-01content/journals/10.1049/el_19750011