Matthias Christandl Artur Ekert Michal Horodecki Pawel Horodecki Jonathan Oppenheim Renato Renner Unifying Classical and Quantum Key Distillation. 456-478 2007 conf/tcc/2007 TCC http://dx.doi.org/10.1007/978-3-540-70936-7_25 db/conf/tcc/tcc2007.html#ChristandlEHHOR07