"Variable Dimension Complexes, Part II: A Unified Approach to Some Combinatorial Lemmas in Topology."

Freund, Robert M. Mathematics of Operations Research Vol. 9, No. 4 (1984): 498-509.

"Optimal Scaling of Balls and Polyhedra."

Eaves, B.C. and Robert M. Freund. Mathematical Programming Vol. 23, No. 1 (1982): 138-147.

"A Constructive Proof of Tucker's Combinatorial Lemma."

Freund, Robert M., and Michael J. Todd. Journal of Combinatorial Theory Vol. 30, No. 3 (1981): 321-325.