How to locate the generic Bosch O2 sensor?

[frahm at jila.colorado.edu]

I'm running a three-wire Bosch O2 sensor for a 1989 Ford Taurus on my
Porsche 944, it works fine, just have to splice the wires.  I think I
asked for one for the 3.0l Taurus, more or less at random.  $40 or so
at my local.

-Joel.