Guarnieri, M. (2012). "The age of vacuum tubes: Early devices and the rise of radio communications". IEEE Ind. Electron. M.6 (1): 41–43. doi:10.1109/MIE.2012.2182822.
Guarnieri, M. (2012). "The age of vacuum tubes: the conquest of analog communications". IEEE Ind. Electron. M.6 (2): 52–54. doi:10.1109/MIE.2012.2193274.
Guarnieri, M. (2012). "The age of Vacuum Tubes: Merging with Digital Computing". IEEE Ind. Electron. M.6 (3): 52–55. doi:10.1109/MIE.2012.2207830.