«Fifty years of telex». Telecommunication Journal51: 35. 1984. Consultado el 18 de mayo de 2017. «Just over fifty years ago, in October 1933, the Deutsche Reichspost as it was then known, opened the world's first public teleprinter network.»
Herbst, Kris (14 de noviembre de 1988). «The competition» (46). IDG Network World Inc. p. 68. ISSN0887-7661. Consultado el 29 de diciembre de 2017. «Telex originated in Germany and rapidly expanded to other countries after World War II.»
Herbst, Kris (14 de noviembre de 1988). «The competition» (46). IDG Network World Inc. p. 68. ISSN0887-7661. Consultado el 29 de diciembre de 2017. «Telex originated in Germany and rapidly expanded to other countries after World War II.»
«The Text Message Turns 20: A Brief History of SMS». theweek.com. 3 de diciembre de 2012. Consultado el 2 de febrero de 2016. «1984 [...] Sitting at a typewriter at his home in Bonn, Germany, Friedhelm Hillebrand types random sentences and questions, counting every letter, number, and space. Almost every time, the messages amount to fewer than 160 characters — what would become the limit of early text messages — and thus the concept for the perfect-length, rapid-fire 'short message' was born.»
