Dawn of Apocalypse
X-Men Chronicles #1
Tales from the Age of Apocalypse:  Sinister Bloodline #1
X-Man #-1
X-Men Chronicles #2
Tales from the Age of Apocalypse #1
Age of Apocalypse:  The Chosen #1
X-Universe #1-2

Age of Apocalypse 1
X-Men Alpha
Astonishing X-Men #1
Generation Next #1
Gambit and the X-Ternals #1
X-Calibre #1
Weapon X #1
Amazing X-Men #1
Factor X #1
X-Man #1
Astonishing X-Men #2
Amazing X-Men #2
Generation Next #2
Gambit and the X-Ternals #2
X-Calibre #2
Weapon X #2
Factor X #2
X-Man #2
Astonishing X-Men #3
Factor X #3

Age of Apocalypse 2
Amazing X-Men #3
Generation Next #3
Gambit and the X-Ternals #3
X-Calibre #3
Weapon X #3
X-Man #3
Astonishing X-Men #4
Generation Next #4
X-Calibre #4
Weapon X #4
Gambit and the X-Ternals #4
Amazing X-Men #4
X-Man #4
Factor X #4
X-Men Omega

The mapping continues:
X-Men 1995-2001
2001-2008
Messiah Era