P. Chardaire, J. Lutton, and A. Sutter, Upper and Lower Bounds for the Two-Level Simple Plant Location Problem, Annals of Operations Research, vol.86, pp.117-140, 1999.
DOI : 10.1023/A:1018942415824

B. Gendron, P. Khuong, and F. Semet, A Lagrangian-Based Branchand-Bound Algorithm for the Two-Level Uncapacitated Facility Location Problem with Single Assignment Constraints, Transportation Science

J. Krarup and P. M. Pruzan, The simple plant location problem: Survey and synthesis, European Journal of Operational Research, vol.12, issue.1, pp.36-81, 1983.
DOI : 10.1016/0377-2217(83)90181-9

S. Tragantalerngsak, J. Holt, and M. Rönnqvist, Lagrangian heuristics for the two-echelon, single-source, capacitated facility location problem, European Journal of Operational Research, vol.102, issue.3, pp.611-625, 1997.
DOI : 10.1016/S0377-2217(96)00227-5