N. A. Bazhanov, D. S. Bulyanitsa, A. I. Kovalev, V. V. Polyakov, V. Yu. Trautman, E. D. Trifonov, A. V. Shvedchikov, “Superradiance at the NMR frequency in a proton spin system in a solid”, Fizika Tverdogo Tela, 31:2 (1989), 206–208
Organisations
B. P. Konstantinov Leningrad Nuclear Physics Institute of the USSR Academy of Sciences