The code book : the science of secrecy from ancient Egypt to quantum cryptography / Simon Singh
Installation of the first direct telecomunications link between the Netherlands and Denmark by means of repeatered submarine coaxial cable / Standard Telephones and Cables Limited
De Rijkstelegraaf in Nederland : hare opkomst en ontwikkenling (1852 - I December - 1902) / geillustreerd Gedenkboek
Geschiedenis Van de Rijkstelegraaf : 1852-1952 / Dr. E.A.B.J. Ten Brink; C. W. Schell