1. RR Jenness,Analog computation and simulation laboratory roach, Allyn and Bacon Inc, Boston, 1965, p. 5.
2. S Fifer,Analogue computation, McGraw Hill, New York, 1961.
3. AS Jackson,Analog computation, McGraw Hill, New York, 1960.
4. C L Johnson,Analog computer tech, McGraw Hill, New York, 1956.