This episode isn't as heavily researched and is more just a quick retelling of the character's history. As such, this isn't really a references section and is more like a "recommended reading."
*Most, if not all, of these comics are available on Marvel Unlimited*
Jean Grey’s death and return as The Phoenix:
Uncanny X-Men 100-101
More on the Phoenix and Jean Grey story:
Phoenix Saga (Uncanny X-Men 101-108)
Dark Phoenix Saga (Uncanny X-Men 129-138)
Madalyne Pryor’s fall from grace:
X-Men: Inferno (The Uncanny X-Men 239-243, X-Factor vol. 1, 36-40 & Annual 4)
Baby Nathan’s abduction and infection:
X-Factor vol. 1 66-68
Cable’s first appearances:
The New Mutants 86-87
Cables childhood:
The Adventures of Cyclops and Phoenix 1-4
Rachel Summers first appearance:
The Uncanny X-Men 141
Excalibur’s origin:
Excalibur Special Edition 1: The Sword is Drawn
Cables Origin:
https://www.cbr.com/comic-book-legends-revealed-201/
Walter Simonson on Cable’s creation:
Liefeld on Cable’s creation:
Rachel and Captain Britain switching places:
www.cbr.com/captain-britain-brianic-excalibur/amp/
Excalibur vol.1 75
Cable’s youth:
Askani'son #1-4
Information on Canaan:
https://www.livescience.com/amp/56016-canaanites.html
Cable’s mercenary team and the turn against them:
Cable: Blood and Metal #1-2
Cables death and replacement:
Extermination #1-5
