1. Weinstein, B., , Die lgrdstr6me im Deutschen Reichstelegraphengebiet und ihr Zusammenhang mir den Erdmagnetischen Erscheinungen. Mir einen, atlas, Braunschweig, 1900,
2. A Study of Pressure and Temperature Effects in Earth-Current Measurements;Mauchly;Terr. Mag.,1918
3. Cf. Article by Ubach, José, , , S. J., Boletin mensual del Observatorio del Ebro, , Tortosa, , vol. 1, , (No. 1.) , January, , 1910, , pp. 51– -55 , and Mémoires de l'Obs. de l'Ebre. No. 4, La Section Eléctrique, par J. Garcia Mollá, S. J., 1910, pp. 95–119.
4. On Vertical Electric Currents, etc;Bauer;Terr. Mag.,1911
5. On Earth-Currents and Magnetic Variations;Steiner;Terr. Mag.,1908