Three-dimensional magnetic and abundance mapping of the cool Ap star HD 24712 - I. Spectropolarimetric observations in all four Stokes parameters
N. Rusomarov, O. Kochukhov, N. Piskunov, S. V. Jeffers, C. M. Johns-Krull, C. U. Keller, V. Makaganiuk, M. Rodenhuis, F. Snik, H. C. Stempels and J. A. Valenti
