1. K. B. Miller, Telephone Theory and Practice, vol. III, Automatic Switching, McGraw-Hill, New York, 1933.
2. R. Taylor and C. E. Beale, “Common Control System,” Post Off. Electr. Eng. J., vol. 24 (2), pp. 125–131, July 1931.
3. O. Myers, “Markers for the Crossbar Toll System,” Bell Lab. Res., vol. 22, pp. 499–504, August 1944.
4. H. E. Vaughan, “Introduction to No. 4 ESS,” Int. Switching Symp., Boston, Massachusetts, 1972, pp. 19–25.
5. D. H. Carbaugh, G. G. Drew, H. Ghiron, and E. S. Hoover, “No. 1 Call Processing,” Bell Syst. Tech. J., vol. 43(5), pt. 2, pp. 2483–2531, September 1964.