Sørensen, O. Max Planck Institute for the Physics of Complex Systems, Max Planck Society;
Sogo, T., Sørensen, O., Jensen, A. S., & Fedorov, D. V. (2005). The zero-range approximation applied to the N-boson problem. Journal of Physics B-Atomic Molecular and Optical Physics, 38(7), 1051-1075.