Neutron-proton scattering at next-to-next-to-leading order in Nuclear Lattice Effective Field Theory Jose Manuel Alarcón, Dechuan Du, Nico Klein, Timo A. Lähde, Dean Lee, Ning Li, Bing-Nan Lu, Thomas Luu and Ulf-G. Meißner Eur. Phys. J. A, 53 5 (2017) 83 Published online: 08 May 2017 DOI: 10.1140/epja/i2017-12273-x