“Study of Colour Measurements of Leather Dyed with Walnut Bark Natural Dye: Walnut Bark Dyed Leather” (2010) Biological Sciences - PJSIR, 53(5), pp. 252–257. Available at: http://www.v2.pjsir.org/index.php/biological-sciences/article/view/473 (Accessed: 25 April 2026).