EFFECT OF THE ION MOTION AT LOW ELECTRON DENSITIES ON THE PROFILES OF THE LINES 4471 Å AND 4922 Å OF HeI C. Fleurier, G. Coulaud et J. Chapelle J. Phys. Colloques, 40 C7 (1979) C7-81-C7-82 DOI: 10.1051/jphyscol:1979740