Preechaya Sanyatit. 2008. 4-dimensional quadratic functional equations of pexider type. Field of Study Mathematics, Chulalongkorn University;
Preechaya Sanyatit. (2008) 4-dimensional quadratic functional equations of pexider type . Chulalongkorn University/Bangkok.
Preechaya Sanyatit. 4-dimensional quadratic functional equations of pexider type. . Bangkok:Chulalongkorn University, 2008.
Preechaya Sanyatit. (2008) 4-dimensional quadratic functional equations of pexider type . Chulalongkorn University/Bangkok.