"Gudlaugur Thorbergsson,Masaaki Umehara","A refinement of Foreman's four vertex theorem and its dual version",,"Kyoto Journal of Mathematics",,"Vol. 52",,"Page 743--758",2013,June
"Syuntaro Oono,Tetsuya Ozawa,Masaaki Umehara","Closed Planar curves without inflections",,"Proc. Amer. Math. Soc.",,"Vol. 141",,"Page 651--665",2013,Feb.