1 R.K. Shelton, S.M. Foreman, L.-S.. Ma, J.L. Hall, H.. Kapteyn, M.. Murnane, M.. Notcutt, and J.. Ye, Optics Letters 27, (2002).
1 J.L. Hall, J.. Ye, L.-S.. Ma, J.-L.. Peng, M.. Notcutt, J.D. Jost, and A.. Marian, in Unknown (World Scientific, St. Andrews, 2002).