1. E. C. Aschenauer et al., The RHIC Spin Program: Achievements and Future Opportunities, arXiv:1304.0079.
2. A. Adare et al., Inclusive double-helicity asymmetries in neutral-pion and eta-meson production in $$\vec p + \vec p$$ collisions at √s = 200 GeV, arXiv: 1402.6296 [hep-ex] 25 Feb 2014.
3. L. Adamczyk et al., Precision Measurement of the Longitudinal Double-spin Asymmetry for Inclusive Jet Production in Polarized Proton Collisions at √s = 200 GeV, arXiv:1405.5134 [hep-ex], 20 May 2014.
4. Q. Xu (for the STAR Collab.), Recent Spin Results from STAR (DSPIN2013, Dubna, Russia, 8–12 October, 2013); http://theor.jinr.ru/~spin/2013/
5. M. Stratmann, Partonic Spin Structure of the Nucleon: Status and Path Forward (MENU 2013, Rome, Italy, 30 September–4 October, 2013); http://menu2013.roma2.infn.it/