("Investigation and Science") in 1976, the French PourlaScience ("For Science") in 1977, the German Spektrum der Wissenschaft ("Spectrum of Science") in 1978
"Supplément de l'article "Les ancêtres français du sudoku"" (PDF). PourlaScience (in French): 1–6. Archived from the original (PDF) on 2006-12-10. Retrieved