@article{zheng:tcad03,                                                         
author = "H. Zheng and E. Mercer and C. Myers",
title = "Modular Verification of Timed Circuits Using Automatic Abstraction",
 Journal = {IEEE Transactions on COMPUTER-AIDED DESIGN of Integrated Circuits and Systems},
volume = 22,
number = 9,
pages = "1138--1153",
year = "2003",
}