Cosmic-Ray Proton and Helium Spectra above 50 GeV Ryan, M. J. ; Ormes, J. F. ; Balasubrahmanyan, V. K. Abstract Publication: Physical Review Letters Pub Date: May 1972 DOI: 10.1103/PhysRevLett.28.1497.3 Bibcode: 1972PhRvL..28.1497R