ノルム多元体
↑ Porteous (1969) p.277
↑ JA Nieto and LN Alejo-Armenta (2000). “Hurwitz theorem and parallelizable spheres from tensor analysis”. Arxiv preprint hep-th/0005184. arXiv:hep-th/0005184.
↑ Kevin McCrimmon (2004). “Hurwitz's theorem 2.6.2”. A taste of Jordan algebras. Springer. p. 166. ISBN 0-387-95447-3. https://books.google.co.jp/books?id=6YG4ycpKMYkC&pg=PA166&redir_esc=y&hl=ja. "Only recently was it established that the only finite-dimensional real nonassociative division algebras have dimensions 1,2,4,8; the algebras were not classified, and the proof was topological rather than algebraic."
↑ Georg Frobenius (1878). “Über lineare Substitutionen und bilineare Formen”. J.