This board creates a +10V and a -10V voltage output with a LM 4040 AIZ 10,0 10V voltage reference.
The 10V are buffered by a non-inverting amplifier with an amplification factor of 1 resulting in a +10V output. This 10V is then amplified by an inverting amplifier with a factor of -1 resulting in a -10V output.
In the second revision I replaced one of the 10k resistors of the non-inverting buffer with a combination of a 8.2k resistor and a 5k trimmer, to allow fine tuning of the output voltage.
The analog computer project files are hosted at GitHub: