@article{zheng:tcad03,                                                         
author = "H. Zheng and C. Myers and D. Walter and S Little and T Yoneda",
title = "Verification of timed circuits with failure-directed abstractions"
 Journal = {IEEE Transactions on COMPUTER-AIDED DESIGN of Integrated Circuits and Systems},
volume = 25,
number = 3,
pages = "403--412",
year = "2006",
}