On the extension of a partial metric to a tree metric.

Alain Guénoche Bruno Leclerc Vladimir Makarenkov On the extension of a partial metric to a tree metric. 229-248 2004 276 Discrete Mathematics 1-3 http://dx.doi.org/10.1016/S0012-365X(03)00294-2 db/journals/dm/dm276.html#GuenocheLM04