Massimo Alioto Luca Fondelli Santina Rocchi Analysis and performance evaluation of area-efficient true random bit generators on FPGAs. 1572-1575 2008 ISCAS http://dx.doi.org/10.1109/ISCAS.2008.4541732 conf/iscas/2008 db/conf/iscas/iscas2008.html#AliotoFR08