Malah, D.; Shenoi, B.A.: 'Synthesis of linear discrete-time-varying systems', Electronics Letters, 1971, 7, (25), p. 745-747, DOI: 10.1049/el:19710511
IET Digital Library, https://digital-library.theiet.org/;jsessionid=1rk751fuhn389.x-iet-live-01content/journals/10.1049/el_19710511