[1] I. Kozma, P. Baum, S. Lochbrunner, and E. Riedle, Opt. Express 11, 3110 (2003).
[2] P. Baum, S. Lochbrunner, and E. Riedle, Opt. Lett. 29, 1686 (2004).
[3] C. G. Durfee Iii, S. Backus, H. C. Kapteyn, and M. M. Murnane, Opt. Lett. 24, 697 (1999).
[4] T. Nagy and P. Simon, Opt. Lett. 34, 2300 (2009).
[5] J. Liu and T. Kobayashi, Opt. Lett. 34, 2402 (2009).
[6] J. Liu and T. Kobayashi, Opt. Commun. 283, 1114 (2010).