Spontaneous Emission of Radiation from an Electron Spin System Feher, G. ; Gordon, J. P. ; Buehler, E. ; Gere, E. A. ; Thurmond, C. D. Abstract Publication: Physical Review Pub Date: January 1958 DOI: 10.1103/PhysRev.109.221 Bibcode: 1958PhRv..109..221F