Mandal WA. Proof without Words: (a+b+c)^2,(a+b-c)^2,(a+b+c)^2-(a+b-c)^2. ojsm [nternet]. 2018 Feb. 17 [cited 2026 Nov. 7];78(1). vailable from: http://voyager.janeway.systems:9999/index.php/OJSM/article/view/6216