Crux Mathematicorum with Mathematical Mayhem, Canadian Mathematical Society, 2007, volume 33, no 6, pp. 354 (online copy) Kurt Schiffler: Problem 1018.
Crux Mathematicorum with Mathematical Mayhem, Canadian Mathematical Society, 2007, Band 33, Nr. 6, S. 354 (Online-Kopie) Kurt Schiffler: Problem 1018.