Varapun Tungvanichkapong. (2008) A Study of Value-added Tax Collection Effort of Tax Collection Unit, 5 Region Office During 2001-2005. <i>NIDA Development Journal</i>, <i>48</i>(1), 1-25.Varapun Tungvanichkapong. "A Study of Value-added Tax Collection Effort of Tax Collection Unit, 5 Region Office During 2001-2005". NIDA Development Journal 48 (2008):1-25.Varapun Tungvanichkapong. A Study of Value-added Tax Collection Effort of Tax Collection Unit, 5 Region Office During 2001-2005. National Institute of Development Administration:ม.ป.ท. 2008.