Alpgard, K., Bertrand, D., Johnson, D., & et al. (1983). Particle Multiplicities in P-bar-p Interactions At Square-root-s= 540-gev. Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics, 121(2-3), 209-215. https://doi.org/10.1016/0370-2693(83)90916-4 (Original work published 1983)