Vintage Cars: Positive Grounded Systems, old drawing, fellow employee

Question
Can you find an old drawing or schematic showing the positive ground, I have a fellow employee that doesn't believe that they exist, a drawing would prove my point, Thanks, Jerry.

Answer
I have several, but I will have to dig them out and put them in a .PDF for you. Can you send me your email address, and I will forward a Hupmobile wiring schematic showing the positive ground. Most cars up until the 40s were positive ground - I've never been able to find out why this is, or if there are any advantages to either polarity.