1. Hadamard matrices of order 20;Hall,1965
2. Balanced incomplete block designs and related designs;Hanani;Discrete Math.,1975
3. Problem 863;Schmidt;Math. Mag.,1973
4. Schmidt, K. W. & E. T. H. Wang — The weights of Hadamard Matrices (to appear).
5. Combinatories: Room Squares, Sum-Free Sets Hadamard Matrices;Wallis,1972