1. Agayan, S.S.: Hadamard Matrices and their Applications. Springer (1985)
2. Bernstein, D.J.: Arbitrarily tight bounds on the distribution of smooth integers. In: Bennett, M.A., et al. (eds.) Number Theory for the Millennium I, pp. 49–66. AK Peters (2002)
3. Craigen, R., Kharaghani, H.: Hadamard matrices and Hadamard designs. In: Colbourn, C.J., Dinitz, J.H. (eds.) Handbook of Combinatorial Designs, 2nd edn., pp. 273–280. CRC Press (2007)
4. Craigen, R., Seberry, J., Zhang, X.: Product of four hadamard matrices. JCT A 59, 318–320 (1992)
5. Doković, D.Z.: Williamson matrices of order 4n for n = 33, 35, 39. Discrete Math. 115, 267–271 (1993)