Rudolf Mosse-Code y Mosse Condenser / J. Kähler; Departamento de código Rudolf Mosse
The ABC universal commercial electric telegraphic code : specially adapted for the use of financiers, merchants, shipowners, brokers, agents / W. Clauson-Thue
International cabel directory of the world in conjuction with western union telegraphic code system / International Cable Directory Company
Guide to the correction of errors in code (and other) telegrams