Pawel Szalachowski Daniël Reijsbergen Ivan Homoliak Siwei Sun StrongChain: Transparent and Collaborative Proof-of-Work Consensus. 819-836 2019 USENIX Security Symposium https://www.usenix.org/conference/usenixsecurity19/presentation/szalachowski conf/uss/2019 db/conf/uss/uss2019.html#SzalachowskiRHS19