Daniele Micciancio Scott Yilek The Round-Complexity of Black-Box Zero-Knowledge: A Combinatorial Characterization. 535-552 2008 TCC http://dx.doi.org/10.1007/978-3-540-78524-8_29 conf/tcc/2008 db/conf/tcc/tcc2008.html#MicciancioY08