Historical Rules · 1 April 2011
Rule 205.4
Official source text from the 1 April 2011 Rules release
Players may include cards from any printing in their constructed decks if those cards appear in sets allowed in that format (or those cards are specifically allowed by the _Magic_ Tournament Rules). See the _Magic_ Tournament Rules for the current definitions of the constructed formats (http://www.wizards.com/Magic/TCG/Events.aspx?x=dci/doccenter/home).