Steiner Minimal Trees on Sets of Four Points. - Ding-Zhu Du; Frank K. Hwang; G. D. Song; G. Y. Ting (Discret. Comput. Geom., 1987)

A Decomposition Theorem on Euclidean Steiner Minimal Trees. - Frank K. Hwang; G. D. Song; G. Y. Ting; Ding-Zhu Du (Discret. Comput. Geom., 1988)