O. Gröning, R. Clergereaux, L.-O. Nilsson, P. Ruffieux, P. Gröning, and L. Schlapbach, “Prospects and Limitations of Carbon Nanotube Field Emission Electron Sources”, Chimia, vol. 56, no. 10, p. 553, Oct. 2002, doi: 10.2533/000942902777680081.