Proctor, M. (1977). "On Backus' necessary condition for dynamo action in a conducting sphere". Geophysical & Astrophysical Fluid Dynamics. 9 (1). ss. 89-93. Bibcode:1977GApFD...9...89P. doi:10.1080/03091927708242317.
Proctor, M. (1977). "On Backus' necessary condition for dynamo action in a conducting sphere". Geophysical & Astrophysical Fluid Dynamics. 9 (1). ss. 89-93. Bibcode:1977GApFD...9...89P. doi:10.1080/03091927708242317.