by Angelov, I.M., Urshev, L.K., Yanev, A.S., Kokontchev, L.Z., Spasov, A.Y., Petrov, M.M., Stoev, I.K., Georgiev, S.
Published in 1988 18th European Microwave Conference (01.09.1988)

by Angelov, I.M., Urshev, L.K., Stoev, I.K., Spasov, A.Y., Koumanov, N.Y., Georgiev, S.S., Vassilev, V.P., Dementienko, V.
Published in 1989 19th European Microwave Conference (01.09.1989)