[sdiy] An unusual opamp only four quadrant multiplier

[John Speth]

This might not be the exact same article from 2011 but it's probably close:

http://nopr.niscair.res.in/bitstream/123456789/6896/1/IJPAP%2048%281%29%2067-70.pdf 
<http://nopr.niscair.res.in/bitstream/123456789/6896/1/IJPAP%2048%281%29%2067-70.pdf>

It has a schematic.

JJS