Constraints for the nuclear sea quark distributions from the Drell-Yan process at the SPS K.J. Eskola, V.J. Kolhinen, C.A. Salgado and R.L. Thews Eur. Phys. J. C, 21 4 (2001) 613-620 Published online: 15 November 2001 DOI: 10.1007/s100520100771