Bruno Becker Paolo Giulio Franciosa Stephan Gschwind Thomas Ohler Gerald Thiemt Peter Widmayer An Optimal Algorithm for Approximating a Set of Rectangles by Two Minimum Area Rectangles. 13-25 1991 conf/cga/1991 Workshop on Computational Geometry db/conf/cga/cga1991.html#BeckerFGOTW91