Napaporn Tengkaew. 2004. The opinion of people in Bangkok Metropolis towards chemical residue free vegetables. Field of Study Environment, Mahidol University;
Napaporn Tengkaew. (2004) The opinion of people in Bangkok Metropolis towards chemical residue free vegetables . Mahidol University/Bangkok.
Napaporn Tengkaew. The opinion of people in Bangkok Metropolis towards chemical residue free vegetables. . Bangkok:Mahidol University, 2004.
Napaporn Tengkaew. (2004) The opinion of people in Bangkok Metropolis towards chemical residue free vegetables . Mahidol University/Bangkok.