@inproceedings{fms-mctc-09,
author = {Fekete, S\'{a}ndor P. and Joseph S. B. Mitchell and Schmidt, Christiane},
 title = {Minimum covering with travel cost},
 booktitle = {Proceedings of the 20th International Symposium on Algorithms and Computation},
pages = {393--402}
 year = {2009},
  }