Chao-Wen Huang, Chia-Wei Lee, Huang-Ming Gao, Sun-Yuan Hsieh. The internal Steiner tree problem: Hardness and approximations. J. Complexity, 29(1):27-43, 2013. [doi]
@article{HuangLGH13,
title = {The internal Steiner tree problem: Hardness and approximations},
author = {Chao-Wen Huang and Chia-Wei Lee and Huang-Ming Gao and Sun-Yuan Hsieh},
year = {2013},
doi = {10.1016/j.jco.2012.08.005},
url = {http://dx.doi.org/10.1016/j.jco.2012.08.005},
researchr = {https://researchr.org/publication/HuangLGH13},
cites = {0},
citedby = {0},
journal = {J. Complexity},
volume = {29},
number = {1},
pages = {27-43},
}