Relation between photospheric magnetic field and chromospheric emission R. Rezaei, R. Schlichenmaier, C. A. R. Beck, J. H. M. J. Bruls and W. Schmidt A&A, 466 3 (2007) 1131-1144 Published online: 24 April 2007 DOI: 10.1051/0004-6361:20067017