I was watching a video on Voltage reference for checking the accuracy of DDM.. How do you guys check the accuracy of your meters??? I was thinking about building a calibration box with voltage,resistance,and current.. But my only problem is that I don't have a meter with a calibration cert or even a meter with that kind of accuracy.. My best meter is a Fluke 87 series II and working on getting a Uni-T 61-E.. What do you guys think ???