↑ Hillary Mayell (ngày 31 tháng 3 năm 2004). “Is Bead Find Proof Modern Thought Began in Africa?”. National Geographic News. tr. 2. Truy cập ngày 20 tháng 5 năm 2016. Work published in 2001 described 28 bone tools and thousands of pieces of ocher—a mineral used to create paint for body decoration and cave painting—dated at roughly 70,000 years old found in Blombos Cave in South Africa. Two pieces of ocher appear to be marked with abstract lines that could be viewed as artistic expression.
