1. J. Akiyama and R. L. Graham, Risan Suugaku Nyumon (Introduction to Discrete Math ematics) (in Japanese), Asakura Shoten (1993)
2. J. Akiyama, X. Chen, G. Nakamura, M. J. Ruiz, Minimum Perimeter Developments of the Platonic Solids, Thai J. Math. 9 (2011), no. 3, 461-481
3. F. R. K. Chung and R. L. Graham, Steiner Trees for Ladders, Annals of Discrete Mathematics 2 (1978), 173-200
4. D. Z. Du, F. K. H Wang, J. F. Weng and S. C. Chao, Steiner minimal trees for points on a circle, Proc. Amer. Math. Soc. 95, (1985), 613-618
5. M. R. Garey, R. L. Graham and D. S. Johnson, The complexity of computing Steiner minimal trees, SIAM J. Appl. Math., 32, (1977), 288-311