Useful Links:

Textbook Website:
Digital Integrated Circuits, 2nd Ed. (by Prof. Rabaey, University of California, Berkeley)
Help on Unix Commands:
Commonly Used Unix Commands (from Computer Center, New Mexico Tech.)
VHDL Reference:      
VHDL Cookbook, 1st Ed. (by Peter J. Ashenden)
Synopsys Help Page:
Synosys Help Page (from Mosaic Lab. Group, University of North Carolina, Charlotte)
Synopsys Inc.:
Synosys Inc. Website