Ragazzini, John R.; Randall, Robert H.; Russell, Frederick A. «Analysis of Problems in Dynamics by Electronic Circuits». Proceedings of the IRE. IEEE, 35, 5, 5-1947, pàg. 444–452. DOI: 10.1109/JRPROC.1947.232616. ISSN: 0096-8390.
Ragazzini, John R.; Randall, Robert H.; Russell, Frederick A. «Analysis of Problems in Dynamics by Electronic Circuits». Proceedings of the IRE. IEEE, 35, 5, 5-1947, pàg. 444–452. DOI: 10.1109/JRPROC.1947.232616. ISSN: 0096-8390.