3 Op-Amp Differential Instrumentation Amp
The Input zeners and diodes form a protective clamp for all voltages above VCC-VDD. If supply is changed to +12 -12 change zeners to 12V zeners. Use similar Zeners at output to protect Output from being zapped by overvoltages or high energy - voltage*frequency transients. Add plastic capacitors across Rf for damping AC operation or ripple. Also avoid floating inputs by providing a bias.

There is also listed below all the Interactive Tutorials using Virtual Electronic Components. Instrumentation Differential Amplifier using Three Op-Amps, Slide the Potentiometers and vary the mV Source, See Output DVM. This is close to the Ideal Instrumentation Amp, High Z and Excellent CMRR.