Zohar Shay Karnin Amir Shpilka Black Box Polynomial Identity Testing of Generalized Depth-3 Arithmetic Circuits with Bounded Top Fan-In. 280-291 2008 IEEE Conference on Computational Complexity http://doi.ieeecomputersociety.org/10.1109/CCC.2008.15 conf/coco/2008 db/conf/coco/coco2008.html#KarninS08