Automatic Error Bounds on Real Zeros of Rational Functions
A procedure for implementing an interval arithmetic
version of the Newton-Raphson method is 
proposed.  The procedure require only a starting interval
over which the zeros of a given rational function 
are to be located.  The method automatically provides bounds 
for roundoff error.
CACM November, 1966
Dargel, R. H.
Loscalzo, F. R.
Witt, T. H.
