Raul Rojas, "Reviews", IEEE Annals of the History of Computing, vol.25, no. 2, pp. 83-85, April-June 2003, doi:10.1109/MAHC.2003.1203061
1. Evidence shows that two well-know German scientists, Herbert Welker and Herbert Mataré, who were employed by the French post office after WW II to develop semiconductor diodes, observed a triode effect while working with polycrystalline germanium. This caused much excitement in European electronic circles until the full scope of the research at the Bell Laboratories was released in the early summer of 1948. Actually, Bardeen's greatest worry during the period of secrecy was that Walter Schottky, another brilliant scientist and engineer, would win the race to the triode. Mataréhas continued research and development in electronics.