@INPROCEEDINGS{Absi2007a,
  author = {N. Absi and S. Kedad-Sidhoum},
  title = {Lagrangean heuristics for capacitated lot-sizing problem with setup
	times, safety stocks and shortage costs},
  booktitle = {Eighth Workshop on Models and Algorithms for Planning and Scheduling
	Problems (MAPSP'2007)},
  year = {2007},
  pages = {1--3},
  month = {July}
}