@article{
author = {Anupam Gupta and  Aravind Srinivasan},
title = {An Improved Approximation Ratio for the Covering Steiner Problem},
journal = {Theory of Computing},
year = {2006},
volume = {2},
number = {1},
pages = {53-64},
publisher = {Theory of Computing},
eprint = {toc:v002/a003},
URL = {http://www.theoryofcomputing.org/articles/main/v002/a003},
}