J. C.  Johannsen, Ulstrup, S., Crepaldi, A., Cilento, F., Zacchigna, M., Miwa, J. A., Cacho, C., Chapman, R. T., Springate, E., Fromm, F., Raidel, C., Seyller, T., King, P. D. C., Parmigiani, F., Grioni, M., and Hofmann, P., ?Tunable carrier multiplication and cooling in graphene?, Nano Letters, vol. 15, pp. 326-331, 2015.