Kuzmin A.D. , Kardashev N.S. , Nikolaev N.Y. , Novikov A.Y. , Popov M.V. , Soglasnov V.A. , Smirnova T.V. , Sieber W.. , Wielebinski R.. Simultaneous single-pulse observations of radio pulsars over a broad frequency range. Astron. and Astrophys. , Vol.163,N1/2 , с. P.114-118 , 01.1986