R. Horsley, Y. Nakamura, H. Perlt, D. Pleiter, P. E. L. Rakow, G. Schierholz, A. Schiller, H. Stüben, F. Winter, and J. M. Zanotti (QCDSF-UKQCD Collaboration)
Phys. Rev. D 85, 034506 (2012) – Published 22 February 2012
Oliver K. Baker, Michael Betz, Fritz Caspers, Joerg Jaeckel, Axel Lindner, Andreas Ringwald, Yannis Semertzidis, Pierre Sikivie, and Konstantin Zioutas
Phys. Rev. D 85, 035018 (2012) – Published 17 February 2012