"Shoichi Fujimori,Young Wook  Kim,Sung-Eun  Koh,Wayne Rossman,Heayong  Shin,Masaaki Umehara,Kotaro Yamada,Seong-Deog Yang","Zero mean curvature surfaces in Lorentz-Minkowski 3-space which change type across a light-like line",,"OSAKA JOURNAL OF MATHEMATICS",,"Vol. 57","No. 1","pp. 285-297",2015,Jan.
"Shoichi Fujimori,Young Wook  Kim,Sung-Eun  Koh,Wayne Rossman,Heayong  Shin,Masaaki Umehara,Kotaro Yamada,Seong-Deog Yang","Zero mean curvature surfaces in Lorentz-Minkowski 3-space and 2-dimensional fuluid mechanics",,"Math. J. Okayama Univ.",,"Vol. 57","No. 1","pp. 173-200",2015,Jan.