The Heidelberg polarized alkali source E. Steffens, W. Dreves, P. Egelhof, D. Kassen, W. Weiss, P. Zupranski et D. FickRev. Phys. Appl. (Paris), 12 10 (1977) 1567-1570DOI: https://doi.org/10.1051/rphysap:0197700120100156700