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Where can I find the construction for a skew Hadamard matrix of order 756?

According to multiple papers (e.g. Koukouvinos and Stylianou - On skew-Hadamard matrices and Seberry - On skew Hadamard matrices) this matrix has been constructed. However, none of the papers I have found give a reference to the actual construction that is being used to obtain it. In particular, the paper by Seberry (published in 1978) is the oldest I could find which states that the construction is known.

Note that I also couldn't find a construction for a skew Hadamard matrix of order 292 (see this question), which also appeared as known for the first time in that same 1978 paper, so it is possible that they were created using the same construction.

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The matrix can be constructed using Theorem 7 from Seberry - On skew Hadamard matrices, by setting $m = 1$ and $n = 28$.

The amicable Orthogonal Design of type $((1, 27); (28))$ are constructed from amicable hadamard matrices of order 28 (construction taken from (v, k, λ) Configurations and Hadamard matrices - Wallis, for the relation between amicable Hadamard matrices and amicable OD see Lemma 5.4 from Orthogonal Designs - Seberry).

Lastly, the OD of type $(1, 1, 26)$ is constructed using the Goethals-Seidel Array and sequences taken from Table G.7 of Orthogonal Designs - Seberry

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