Rainer Schrader. Approximations to clustering and subgraph problems on trees. Discrete Applied Mathematics, 6(3):301-309, 1983. [doi]
@article{Schrader83,
title = {Approximations to clustering and subgraph problems on trees},
author = {Rainer Schrader},
year = {1983},
doi = {10.1016/0166-218X(83)90083-5},
url = {http://dx.doi.org/10.1016/0166-218X(83)90083-5},
researchr = {https://researchr.org/publication/Schrader83},
cites = {0},
citedby = {0},
journal = {Discrete Applied Mathematics},
volume = {6},
number = {3},
pages = {301-309},
}