Information on the implementation of "Spice"

[cgs at umd5.UUCP]

Can anyone steer me to references, or can explain the general principles
used in the "Spice" program to calculate solutions of arbitrary circuits?
That is, what sort of abstract models/algorithms are used so the program
can analyze circuits? I'm not asking how a person goes about analyzing
a circuit, I'm asking how does one program a computer to do it for such
wide varieties and levels of complication that Spice calculates? Programming
a computer to analyze specific, predetermined topologies is not the same
thing as Spice, either.
I'm asking you folks on behalf of my immediate employer for the purposes
of his continued education (and my own as well), in case anyone wants to know.
ad-thanks-vance!
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