Mandal, W. A. (2018) “Proof without Words: (a+b+c)^2,(a+b-c)^2,(a+b+c)^2-(a+b-c)^2”, Ohio Journal of School Mathematics, 78(1). vailable at: http://voyager.janeway.systems:9999/index.php/OJSM/article/view/6216 (ccessed: 7 November 2026).