@Article{sagnac21,
	author =	{Hurst, R.B. and Wells, J.-P.R. and Stedman, G.E.},
	title = 	"{An elementary proof of the geometrical dependence of the Sagnac effect}",
	journal =	{J. Opt. A: Pure Appl. Opt.},
	volume =	{9},
	month =	{September},
	year =	{2007},
}