Rahman, M., Y. Haque, S. Das, M. Hossain, and M. Rashid. “Study of Attractive Nonlinearity by 1-D Nonlinear Schrödinger Equation in the Bose–Einstein Condensate”. Journal of Bangladesh Academy of Sciences, vol. 33, no. 1, July 2009, pp. 87-98, doi:10.3329/jbas.v33i1.2953.