Areeudomwong, Pattanasin, Rungthip Puntumetakul, and Naruemon Leerayuwat. 2009. “Reliability of surface electromyography measurement on lumbar multifidus muscles and internal oblique muscles during sub-maximal voluntary muscle contraction in healthy Thai participants”. Archives of Allied Health Sciences 21 (3). Khon Kaen, Thailand:277-86. https://he01.tci-thaijo.org/index.php/ams/article/view/66161.