Piyasawat Navaratana Na Ayudhya และ Anawach Sangswang. (2011) Multi-rating electronic ballast for fluorescent lamps based on operating frequency determination. King mongkut’s university of technology thonburi:ม.ป.ท.Piyasawat Navaratana Na Ayudhya และ Anawach Sangswang. 2011. Multi-rating electronic ballast for fluorescent lamps based on operating frequency determination. ม.ป.ท.:King mongkut’s university of technology thonburi;Piyasawat Navaratana Na Ayudhya และ Anawach Sangswang. Multi-rating electronic ballast for fluorescent lamps based on operating frequency determination. ม.ป.ท.:King mongkut’s university of technology thonburi, 2011. Print.