00433nab a2200157 4500 20260406180400.0 260224s xxu Thomas, Mark 11654 Balancing act 12/09/06 ; 15/07/02 5 p. Vol. 73, Issue 3 (mar. 2000) ; p. 58-63 Hart's E & P Thomas, Mark 11654 ARTICULO ddc 135471 135471