National Internal Revenue Code of 1997 : as amended, consolidated, and annotated up to March 1, 2009 : Republic Act no. 8424, as amended by R.A. nos. 8761, 9010, 9224, 9238, 9243, 9294, 9334, 9337, 9361 & 9504 / Eufrocina M. Sacdalan-Casasola, Rosario S. Santiago-Bernaldo.