Onanong Sornnarai. 2004. The participation of labour in trade union for prevention of an unsafe workplace environment : a case study among metal product machine and equipment manufacturing industry. Field of Study Population Education, Mahidol University;

Onanong Sornnarai. The participation of labour in trade union for prevention of an unsafe workplace environment : a case study among metal product machine and equipment manufacturing industry. . Bangkok:Mahidol University, 2004.

Onanong Sornnarai. (2004) The participation of labour in trade union for prevention of an unsafe workplace environment : a case study among metal product machine and equipment manufacturing industry . Mahidol University/Bangkok.