"Akamine Shintaro,Masaaki Umehara,Kotaro Yamada","Improvement of the Bernstein-type theorem for space-like zero mean curvature graphs in Lorentz-Minkowski space using fluid mechanical duality",,"Proc. Amer. Math. Soc. Ser. B",,"Vol. 7",,"pp. 17-27",2020,Feb.
"S. Akamine,A. Honda,M. Umehara,K.Yamada","Bernstein-type theorem for zero mean curvature hypersurfaces without time-like points in Lorentz-Minkowski space",,"Bulletin of the Brazilian Mathematical Society, New Series",,,,"  https://doi.org/10.1007/s00574-020-00196-8",2020,Jan.