raie à 21 cm

[1994] 21 cm line of atomic hydrogen ; J. W. V. Storey ; M. C. B. Ashley ; M. Naray ; J. P. Lloyd ; American Journal of Physics 62 (dec 1994) p. 1077 [lien]
[2006] Cosmology at low frequencies: The 21 cm transition and the high-redshift Universe ; Steven R. Furlanetto ; S. Peng Oh ; Frank H. Briggs ; Physics Reports 433 (2006) p. 161 [lien]