A polarisation modulation scheme for measuring vacuum magnetic birefringence with static fields G. Zavattini, F. Della Valle, A. Ejlli and G. Ruoso Eur. Phys. J. C, 76 5 (2016) 294 Published online: 24 May 2016 DOI: 10.1140/epjc/s10052-016-4139-0