From the Document: "A balanced budget amendment (BBA) proposes to amend the U.S. Constitution to require that 'outlays shall not exceed revenues.' Constitutional amendments require a two-thirds vote of approval in both houses of Congress as well as ratification by three-fourths of the states. [...] Proposed BBAs have historically included additional provisions that may be as contentious as the requirement that outlays not exceed revenues. Such provisions are summarized below."
CRS Insight, IN10884
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html