Gardner, Martin.
Mathematical Puzzles & Diversions / - 1st ed / - New York 20 : Simon and Schuster, Inc.. - p.254 :
Mathematics
B0bMY4 / K1
Mathematical Puzzles & Diversions / - 1st ed / - New York 20 : Simon and Schuster, Inc.. - p.254 :
Mathematics
B0bMY4 / K1