Charlton, M., Rizzini, E. L., Venturelli, L., Zurlo, N., Charlton, M., Amsler, C., . . . Werf, D. v. d. (2012). Further evidence for low-energy protonium production in vacuum. The European Physical Journal Plus, 127(10), . doi:10.1140/epjp/i2012-12124-9

Charlton, Michael, et al. "Further Evidence for Low-energy Protonium Production in Vacuum." The European Physical Journal Plus 127, no. 10 (2012).

Charlton, Michael, et al. "Further Evidence for Low-energy Protonium Production in Vacuum." The European Physical Journal Plus 127.10 (2012).