Wallapak Polasub. 2009. Unemployment benefits and duration of unemployment of workers in Bangkok area. Bangkok:Kasetsart University;
Wallapak Polasub. (2009) Unemployment benefits and duration of unemployment of workers in Bangkok area (รายงานผลงานวิจัย). Kasetsart University:Bangkok.
Wallapak Polasub. Unemployment benefits and duration of unemployment of workers in Bangkok area. Bangkok:Kasetsart University, 2009.
Wallapak Polasub. (2009) Unemployment benefits and duration of unemployment of workers in Bangkok area (รายงานผลงานวิจัย). Kasetsart University:Bangkok.