1) T. Nakamura and K. Hiraoka: Characteristics of Phenomena in Narrow Gap Welding and Proposal New Welding Process at Ultra-Narrow Gap Joint-Development of Ultra-Narrow Gap Welding Process (Report 1)-, Quar. J. JWS, 19-1 (2001), 44-53. (in Japanese)
2) Technical commission on welding arc physics: 溶接プロセスの物理, Kuriki Press, (1996). (in Japanese)
3) V.Y. Malin, WRC Bulletin, 323 (1987).
4) Technical commission on welding press: Narrow Gap Welding, (1984). (in Japanese)