See for example E.L. Carstensen and E.L Sevier: Biological Effects of Transmission Line Fields, New York, 1987; K. Foster: Weak magnetic fields: cancer connection?, In: Phantom Risk, K. Foster, D. Bernstein & P. Huber, Eds., MIT Press, 1993; W.R. Bennett: Cancer and powerlines, Phys. Today 47:23-29, 1994; T.S. Tenforde and W.T. Kaune: Interaction of extremely low frequency electric and magnetic fields with humans, Health Phys. 53:585-606, 1987; R.K. Adair: Constraints on biological efects of weak extremely-low-frequency electromagnetic fields, Phys. Rev. A43:1039-1048, 1991.