Magnetostatic Maxwell's tensors in magnetic media applying virtual works method from either energy or co-energyR. Sanchez-Grandia, R. Vives-Fos and V. Aucejo-GalindoEur. Phys. J. Appl. Phys., 35 1 (2006) 61-68DOI: https://doi.org/10.1051/epjap:2006074