Ankit Gupta Neeraj Kayal Satyanarayana V. Lokam Reconstruction of depth-4 multilinear circuits with top fan-in 2. 625-642 2012 STOC http://doi.acm.org/10.1145/2213977.2214035 conf/stoc/2012 db/conf/stoc/stoc2012.html#GuptaKL12