Historical Rules · 1 October 2012
Rule 711.1
Official source text from the 1 October 2012 Rules release
A double-faced card has a _Magic_ card face on each side rather than a _Magic_ card face on one side and a _Magic_ card back on the other. Each face may have abilities that allow the permanent to "transform," or turn over to its other face. Tokens and cards with a _Magic_ card back can't transform. (See rule 701.25, "Transform.")