Historical Rules · 1 February 2010
Rule 205.4
Official source text from the 1 February 2010 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).