Digital Parallelism, Perpendicularity, and Rectangles. - Ravinder Krishnaswamy; Chul E. Kim (IEEE Trans. Pattern Anal. Mach. Intell., 1987)

On Constructing Binary Space Partitioning Trees. - Ravinder Krishnaswamy; Ghasem S. Alijani; Shyh-Chang Su (ACM Conference on Computer Science, 1990)