Trung, Tran Nam, Igor O Golosnoy, Paul L Lewin, and Tran Khanh Viet Dung. 2012. “A Two-Phase Model for the Development of Positive Surface Discharge in Air”. Petrovietnam Journal 6 (June), 58-69. http://www.pvj.com.vn/index.php/TCDK/article/view/972.