IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, vol. 37, no. 9, page. 1327 - 1333, 1989-09
MICROWAVES & RF, vol. 28, no. 6, page. 75 - &, 1989-06
IEEE TRANSACTIONS ON ELECTRON DEVICES, vol. 36, no. 10, page. 2236 - 2242, 1989-10