* رمز العصا# Shurkin, J.: "Engines of the mind: a history of the computer", W. W. Norton & Co., 1984., p21# Bogoshi, J., Naidoo, K. and Webb, J.: "The oldest mathematical artifact", "Math.
"==See also==*Lebombo Bone*History of mathematics*Paleolithic tally sticks==References====Further reading==# Shurkin, J.: "Engines of the mind: a history of the computer", W. W. Norton & Co., 1984., p21# Bogoshi, J., Naidoo, K. and Webb, J.: "The oldest mathematical artifact", "Math.