by Chen, Y.F., Ivanov, Z.G., Johansson, L.-G., Kojouharov, R.I., Angelov, I.M., Olsson, E., Roddatis, V.A., Stepantsov, E.A., Tzalenchuk, A.Y., Vasiliev, A.L., Claeson, T.
Published in IEEE transactions on applied superconductivity (01.06.1997)

by Angelov, I.M., Stoev, I.K., Ivanov, Z.G., Todorov, B.N., Spasov, A.Y., Kollberg, E.L., Lindstrom, C.O., Wendemo, B.L.
Published in IEEE transactions on microwave theory and techniques (01.02.1992)

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)