1. A lower bound for the Steiner tree problem;Chung, F. R. K.;SIAM J. Appl. Math.,1978
2. Steiner minimal trees;Gilbert, E. N.;SIAM J. Appl. Math.,1968
3. A remark on Steiner minimal trees;Graham, R. L.;Bull. Inst. Math. Acad. Sinica,1976
4. On the problem of Steiner;Melzak, Z. A.;Canad. Math. Bull.,1961
5. Some remarks on the Steiner problem;Pollak, H. O.;J. Combinatorial Theory Ser. A,1978