Venermo, J.; Sihvola, A. (June 2008). "The tangent galvanometer of Johan Jacob Nervander". IEEE Instrumentation & Measurement Magazine. 11 (3): 16–23. doi:10.1109/MIM.2008.4534374. S2CID27081490.
Venermo, J.; Sihvola, A. (June 2008). "The tangent galvanometer of Johan Jacob Nervander". IEEE Instrumentation & Measurement Magazine. 11 (3): 16–23. doi:10.1109/MIM.2008.4534374. S2CID27081490.