Second neighbors inducing common frequencies for bright and dark solitons E. Tala-Tebue, Z. I. Djoufack, A. Kenfack-Jiotsa, F. Kapche-Tagne and T. C. Kofané Eur. Phys. J. Plus, 132 6 (2017) 272 Published online: 22 June 2017 DOI: 10.1140/epjp/i2017-11535-4