@article{JAC_2003__17_1_a4, author = {Nomura, Kazumasa}, title = {Spin models of index 2 and {Hadamard} models}, journal = {Journal of Algebraic Combinatorics}, pages = {5--17}, publisher = {mathdoc}, volume = {17}, number = {1}, year = {2003}, language = {en}, url = {http://geodesic.mathdoc.fr/item/JAC_2003__17_1_a4/} }