J. W. Wescott L. R. Brown Wright
Mean Electron Density Variations of the Quiet Ionosphere No. 12 - February 1960; NBS Technical Note 40-12
Mean Electron Density Variations of the Quiet Ionosphere No. 8 - October 1959; NBS Technical Note 40-8
Mean Electron Density Variations of the Quiet Ionosphere No. 9 - November 1959; NBS Technical Note 40-9