@Article{prec-meas,
	author =	{Bilger, H.R. and Stedman G.E. and Poulton, M.P. and Rowe, C.H. and Li, Z.Y. and Wells, P.V.},
	title = 	"{Ring laser for precision measurement of nonreciprocal phenomena}",
	journal =	{IEEE Transactions on Instrumentation and Measurement},
	volume =	{42},
	number =	{2},
	month =	{April},
	year =	{1993},
}