Canonical Forms and Algorithms for Steiner Trees in Uniform Orientation Metrics.

Marcus Brazil D. A. Thomas J. F. Weng Martin Zachariasen Canonical Forms and Algorithms for Steiner Trees in Uniform Orientation Metrics. 281-300 2006 44 Algorithmica 4 http://dx.doi.org/10.1007/s00453-005-1178-6 db/journals/algorithmica/algorithmica44.html#BrazilTWZ06