1. Rabaey, J., Chandrakasan, A., and Nikolic, B.: ‘Digital integrated circuits: a design perspective’, 2nd(Prentice-Hall, Upper Saddle River, NJ 2003),Sec. 7.6.1
2. Weste, N., and Harris, D.: ‘CMOS VLSI design: a circuits and systems perspective’, (Addison-Wesley, Boston, MA 2005),Sec. 12.4.1