1. We provide a more detailed presentation of how the ENIAC executed the Euler-Heun calculation, including information on programming the accumulators and the Euler-Heun wiring diagram, at maa.org/mathhorizons/supplemental.htm.
2. A few of the many excellent resources on the ENIAC are presented below.
3. First General-Purpose Electronic Computer
4. The Electronic Numerical Integrator and Computer (ENIAC)