Deutscher hochschul-kalender für das wintersemester 1891/1892 / I. Teil
Le miracle de la T.S.F. : histoire du télégraphe et du téléphone / Luce Langevin
ABC of the telephone : A pratical and useful treatise for students and workers in telephony, giving a review of the development of the industry to the present date, and full description of numerous valuable inventions and appliances, together with very many illustrations, diagrams and tables / James E. Homans
Princípios de telecomunicações / Jair cândido de Melo