Código telegráfico Guedes / I. Guedes da Silva
Codigo internacional de signaes; trad. Joaquim Pedro Parente
The british code list : for 1898, for the use of ships at sea, and for signal stations / J. Clarck Hall
Manual de telegraphia : para uso do exercito (approvado por portaria de 28 março de 1898)
Manual para a execução de telegraphia optica
The international code of signals : for the use of all nations / John Clark Hall
250,000 telegraph code indices comprising letter-variations, for indicating series of 3 to 12 numerical or letter variation tables and for forming and interpreting letter-variation tables, with combination tables of 14, 15 and 16 letters and an introduction explaining the application of the tables / F. Jones