Two regimes in the magnetic field response of superconducting MgB2 A. Kohen, F. Giubileo, Th. Proslier, F. Bobba, A. M. Cucolo, W. Sacks, Y. Noat, A. Troianovski and D. Roditchev Eur. Phys. J. B, 57 1 (2007) 21-25 Published online: 01 June 2007 DOI: 10.1140/epjb/e2007-00156-9