Patchareeya Mumsam. 2009. A study of refusal strategies in English used by American native speakers and Thai EFL learners. Faculty of Humanities, Naresuan University;
Patchareeya Mumsam. (2009) A study of refusal strategies in English used by American native speakers and Thai EFL learners . Naresuan University/Phitsanulok.
Patchareeya Mumsam. A study of refusal strategies in English used by American native speakers and Thai EFL learners. . Phitsanulok:Naresuan University, 2009.
Patchareeya Mumsam. (2009) A study of refusal strategies in English used by American native speakers and Thai EFL learners . Naresuan University/Phitsanulok.