Discretely directional luminous vector
光の流れに関する研究

Hirotaka Suzuki, Kotaroh Hirate, Masahito Yasuoka
1995 Journal of the Illuminating Engineering Institute of Japan  
doi:10.2150/jieij1980.79.appendix_156 fatcat:4egcmuifffdt5eotpdyeocbgfy