Pornsawan Inpin. 2000. The proficiency of the staff of Phitsanulok hotels in the use of English for communication. Field of Study English, Naresuan University;
Pornsawan Inpin. (2000) The proficiency of the staff of Phitsanulok hotels in the use of English for communication . Naresuan University/Phitsanulok.
Pornsawan Inpin. The proficiency of the staff of Phitsanulok hotels in the use of English for communication. . Phitsanulok:Naresuan University, 2000.
Pornsawan Inpin. (2000) The proficiency of the staff of Phitsanulok hotels in the use of English for communication . Naresuan University/Phitsanulok.