Bordag, M., Mohideen, U. and Mostepanenko, V.M. (2001) New Developments in the Casimir Effect. Physics Reports, 353, 1-205. (200+ page review paper)
 Lamb, W.E. and Retherford, R.C. (1947) Fine Structure of the Hydrogen Atom by a Microwave Method. Physical Review, 72, 241-243.
 Faria, A.J., Franca, H.M., Gomes, G.G. and Sponchiado, R.C. (2005) The Vacuum Electromagnetic Fields and the Schrodinger Picture. arxiv:quant-ph/0510134v2f. (Faria’s eq. 7 is the same as our equation 2, except in units of Joules/cm3/(radian per second). One must multiply by 2 to get Joule/cm3/Hz and then by c to get watt/cm3/Hz—the units that Einstein uses in his 1917 paper. Faria references Marshall below for a derivation based on 0.5 h of E&M energy per vacuum mode—the minimum energy for a quantum oscillator.)
 Marshall, T.W. (1963) Random Electrodynamics. Proceedings of the Royal Society A, 276, 475.