1. Beamish, D., 1998. GIC risk assessment for NGC: electric fields induced in and around Britain. British Geological Survey. Technical Report WE/98/32C, 1998.
2. Clark, T.D.G., Clarke, E., Thomson, A.W.P., 1998. GIC risk assessment for NGC: geomagnetic disturbances in the British Isles, British geological survey. Technical Report WE/98/28C.
3. Crisford, D.S., 1992. System harmonic voltage measurements at Harker 275kV substation. Technical Audit Unit Report, National Grid Company, TAU/1/92/N.
4. Dong, X., Liu, Y., Kappenman, J.G., 2001. Comparative analysis of exciting current harmonics and reactive power consumption from GIC saturated transformers. Proceedings IEEE PES 2001 Winter Power Meeting, Transformers. IEEE Publication 0-7803-6674-3/00.
5. Elovaara, J., Lahtinen, M., 2000. GIC occurences and GIC test for 400kV system transformer. IEEE Transactions of Power Engineering Society, submitted for publication.