European Journal of CombinatoricsVolume 6, Issue 1, March 1985, Pages 49-57Conference Matrices from Projective Planes of Order 9Author links open overlay panelC.A.J. Hurkens, J.J. SeidelShow moreShareCitehttps://doi.org/10.1016/S0195-6698(85)80021-4Get rights and contentUnder an Elsevier user licenseopen archivePrevious article in issueNext article in issueRecommended articlesCited by (0)Copyright © 1985 Academic Press Inc. (London) Limited. Published by Elsevier Ltd. All rights reserved.