Biswas, Debapriya, and Himadri Lal Das. “Isotropic Basis in a Real Symmetric Bilinear Space: Existence and Construction”. Armenian Journal of Mathematics 17, no. 14 (December 23, 2025): 1–19. Accessed January 3, 2026. https://armjmath.sci.am/index.php/ajm/article/view/1468.