1. A.D. Alexandrovy On the theory of mixed volumes of convex bodies IV. Mat. Sbornik (New Series) 3 (1938), 227–251. (Russian).
2. Thøger Bang, Matrixfunktioner som med et numerisk lilie deficit viser v. d. Waerdens permanenthypothese. Proc Scandinavian Congress, Turkku, 1976.
3. Thøger Bang, On matrix-functions giving a good approximation to the v. d. Waerden permanent conjecture. Københavns Universitet Matematisk Institut, Preprint Series No. 30, 1979.
4. Jacques Dubois, A note on the van der Waerden permanent conjecture. Canad. J. Math. 26 (1974), 352–354.
5. P. J. Eberlein, Remarks on the van der Waerden conjecture II. Linear Algebra Appl. 2 (1969), 311–320.