Physical Review Letters, 84(18), 4047-4051. American Physical Society Physical Review Letters, 84, 4047-4051. American Physical Society Airapetian, A, Amarian, M, Aschenauer, E C, Blouw, J, Bulten, H J, de Witt Huberts, P K A, Guidal, M G, Henkes, T, Ihssen, H, Kolstein, M, van den Brand, J F J, van der Steenhoven, G, van Hunen, J J & Visser, J 2000, ' Evidence for a single-spin azimuthal asymmetry in semi-inclusive pion electroproduction. ', Physical Review Letters, vol. 84, pp. 4047-4051 . https://doi.org/10.1103/PhysRevLett.84.4047 Airapetian, A, Amarian, M, Aschenauer, E C, Blouw, J, Bulten, H J, de Witt Huberts, P K A, Guidal, M G, Henkes, T, Ihssen, H, Kolstein, M, van den Brand, J F J, van der Steenhoven, G, van Hunen, J J & Visser, J 2000, ' Evidence for a single-spin azimuthal asymmetry in semi-inclusive pion ekectroproduction. ', Physical Review Letters, vol. 84, pp. 4047-4051 . https://doi.org/10.1103/PhysRevLett.84.4047 Physical review letters 84(18), 4047-4051 (2000). doi:10.1103/PhysRevLett.84.4047