Ultrashort soliton pulses in the modified nonlinear Schrödinger equation with distributed coefficients in inhomogeneous fibersHai-Qiang Zhang, Bo Tian, Wen-Jun Liu and Yu-Shan XueEur. Phys. J. D, 59 3 (2010) 443-449DOI: https://doi.org/10.1140/epjd/e2010-00161-1