Wanwipa Panyajirawut. 2009. Factors influencing confidence in speaking English : a case study of senior Thai undergraduate students at Srinakharinwiroj University. Bangkok:Thammasat University; DOI : https://doi.nrct.go.th/ListDoi/listDetail?Resolve_DOI=10.14457/TU.res.2009.17
Wanwipa Panyajirawut. (2009) Factors influencing confidence in speaking English : a case study of senior Thai undergraduate students at Srinakharinwiroj University (รายงานผลงานวิจัย). Thammasat University:Bangkok. DOI : https://doi.nrct.go.th/ListDoi/listDetail?Resolve_DOI=10.14457/TU.res.2009.17
Wanwipa Panyajirawut. Factors influencing confidence in speaking English : a case study of senior Thai undergraduate students at Srinakharinwiroj University. Bangkok:Thammasat University, 2009. DOI : https://doi.nrct.go.th/ListDoi/listDetail?Resolve_DOI=10.14457/TU.res.2009.17
Wanwipa Panyajirawut. (2009) Factors influencing confidence in speaking English : a case study of senior Thai undergraduate students at Srinakharinwiroj University (รายงานผลงานวิจัย). Thammasat University:Bangkok. DOI : https://doi.nrct.go.th/ListDoi/listDetail?Resolve_DOI=10.14457/TU.res.2009.17