Progress toward an optical frequency chain at NPL. - Stephen N. Lea; Graham M. MacFarlane; Guilong Huang; Patrick Gill (IEEE Trans. Instrum. Meas., 1999)

An optical frequency standard based on the electric octupole transition in 171Yb+. - Kazumoto Hosaka; Stephen A. Webster; Peter J. Blythe; Adrian Stannard; David Beaton; Helen S. Margolis; Stephen N. Lea; Patrick Gill (IEEE Trans. Instrum. Meas., 2005)