Pham, Thang Van, and Anh Vinh Le. “Orthogonal Systems in Vector Spaces over Finite Rings”. The Electronic Journal of Combinatorics 19, no. 2 (June 28, 2012): P48. Accessed March 27, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v19i2p48.