1. J. Adam et al. (ALICE Collaboration), Nat. Phys. 13, 535 (2017)
2. V. Khachatryan et al. (CMS Collaboration), Phys. Lett. B 765, 193 (2017)
3. E. Cuautle, R. Jimenez, I. Maldonado, A. Ortiz, G. Paic, E. Perez, arXiv:1404.2372 [hep-ph]
4. A. Ortiz, G. Paic, E. Cuautle, Nucl. Phys. A 941, 78 (2015)
5. G.P. Salam, Eur. Phys. J. C 67, 637 (2010)