Orawan Ponngeon. (2005) Respiratory muscle strength in Thai healthy subjects aged 30-70 years. Mahidol University,:ม.ป.ท.Orawan Ponngeon. 2005. Respiratory muscle strength in Thai healthy subjects aged 30-70 years. ม.ป.ท.:Mahidol University,;Orawan Ponngeon. Respiratory muscle strength in Thai healthy subjects aged 30-70 years. ม.ป.ท.:Mahidol University, 2005. Print.