Boyan Valtchanov Alain Aubert Florent Bernard Viktor Fischer Modeling and observing the jitter in ring oscillators implemented in FPGAs. 158-163 2008 DDECS http://dx.doi.org/10.1109/DDECS.2008.4538777 conf/ddecs/2008 db/conf/ddecs/ddecs2008.html#ValtchanovABF08