1. R Carretero-González, J Cuevas-Maraver, D Frantzes-kakis, N Karachalios, P Kevrekidis and F Palmero-Acebedo, Localized excitations in nonlinear complex systems (Springer Science & Business Media, Springer Cham New York Heidelberg Dordrecht London, 2013)
2. Yu S Kivshar and G P Agrawal, Optical solitons: From fibers to photonic crystals (Academic Press, San Diego, 2003)
3. Y V Kartashov, B A Malomed and L Torner, Rev. Mod. Phys. 83, 247 (2011)
4. N N Ahmediev, V I Korneev and U V Kuzmenko, J. Exp. Theor. Phys. 88, 107 (1985)
5. Y V Bludov, D A Smirnova, Yu S Kivshar, N M R Peres and M I Vasilevsky, Phys. Rev. B 89, 035406 (2014)