Breadth-First Ray Tracing Utilizing Uniform Spatial Subdivision. - Koji Nakamaru; Yoshio Ohno (IEEE Trans. Vis. Comput. Graph., 1997)

Enhanced Breadth-First Ray Tracing. - Koji Nakamaru; Yoshio Ohno (J. Graphics, GPU, & Game Tools, 2001)

Ray Tracing for Curves Primitive. - Koji Nakamaru; Yoshio Ohno (WSCG, 2002)

Distance aware ray tracing for curves. - Koji Nakamaru; Toru Matsuoka; Masahiro Fujita (SIGGRAPH Posters, 2012)