r |accessmonthday= ignored (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)↑ "Rules and history of Sudoku from Nikoli".↑ "Combinatorial question on 9x9". Google newsgroups archive. {{cite web}}: Unknown parameter |accessmonthday= ignored (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)↑ Jarvis, Frazer (2006-07-31). "Sudoku enumeration problems". Frazer Jarvis's home page. {{cite web}}: Unknown parameter |accessmonthday= ignored (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)↑ Jarvis, Frazer (2005-09-07). "There are 5472730538 essentially different Sudoku grids ... and the Sudoku symmetry group". Frazer Jarvis's home page. {{cite web}}: Unknown parameter |accessmonthday= ignored (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)↑ "プログラミングパズルに関心のある人は雑談しましょう". プログラミングパズル雑談コーナー / Programming P