@article{RO_2007__41_3_305_0,
     author = {Nguyen, Viet Hung},
     title = {Approximation algorithms for metric tree cover and generalized tour and tree covers},
     journal = {RAIRO - Operations Research - Recherche Op\'erationnelle},
     pages = {305--315},
     publisher = {EDP-Sciences},
     volume = {41},
     number = {3},
     year = {2007},
     doi = {10.1051/ro:2007025},
     mrnumber = {2348005},
     language = {en},
     url = {http://www.numdam.org/articles/10.1051/ro:2007025/}
}