Phatummawadee Kulawattanapaisarn และ Pratin Pimsarn. (2008) Pronoun reference and its effect on writing. Thammasat University:ม.ป.ท.Phatummawadee Kulawattanapaisarn และ Pratin Pimsarn. 2008. Pronoun reference and its effect on writing. ม.ป.ท.:Thammasat University;Phatummawadee Kulawattanapaisarn และ Pratin Pimsarn. Pronoun reference and its effect on writing. ม.ป.ท.:Thammasat University, 2008. Print.