We provide a reference that was missing from [Optica 1, 323 (2014) [CrossRef] ].
© 2015 Optical Society of America
A reference was omitted after the following statement on page 1: “... and Richter et al. studied the role of the Kramers–Hennenberger atom, which displays bound states of a free-electron, to elucidate the higher-order Kerr effect.” The missing reference is .
1. M. Kolesik, J. M. Brown, A. Teleki, P. Jakobsen, J. V. Moloney, and E. M. Wright, “Metastable electronic states and nonlinear response for high-intensity optical pulses,” Optica 1, 323–331 (2014). [CrossRef]
2. M. Richter, S. Patchkovskii, F. Morales, O. Smirnova, and M. Ivanov, “The role of the Kramers-Henneberger atom in the higher-order Kerr effect,” New J. Phys. 15, 083012 (2013). [CrossRef]