1. [Delay time and dynamic switching operation] : J. Millman and H.Taub, PULSE, DIGITAL, AND SWITCHING WAVEFORMS, New York, McGraw-Hill, 1965, Chap.20

2. [Planar structure of BJT] : R.S.Muller and T.I. Kamins, Device Electronics For Integrated Circuits, 2nd ed., Wiley, NY 1977, pp.301-309.

3. [Bipolar trangistor digital circuits - introduction]: A.S.Sedra and K.C.Smith, Microelectronic Circuits, 4th ed., Oxford Univ. press, 1998, Chap.14.