Campbell G.K., M.M. Boyd, J.W. Thomsen, M.J. Martin, S. Blatt, M.D. Swallows, T.L. Nicholson, T.M. Fortier, C.W. Oates, S.A. Diddams, and N.D. Lemke, Science 324, 360-363 (2009).
Ludlow A.D., G.K. Campbell, S. Blatt, M.M. Boyd, M.J. Martin, T.L. Nicholson, M.D. Swallows, J.W. Thomsen, T.M. Fortier, C.W. Oates, and S.A. Diddams, in (World Scientific, 2009), pp. 73-81.
Zirbel J.J., K.-K. Ni, S. Ospelkaus, T.L. Nicholson, M.L. Olsen, P.S. Julienne, C.E. Wieman, J. Ye, and D.S. Jin, Physical Review A 78, (2008).