I was fortunate to see Dr. J in action with the 76ers several times when the Nets played at the RAC from 1977-81 when I was in 8th-11th grade. Many of the visiting teams stayed at the Holiday Inn on Stelton Rd. in South Plainfield.
Some friends and I would often go to the hotel prior to games to get autographs. Erving was always a willing signer. During the four-year span, I had him autograph a few items. My most treasured is this 1972 rookie card. Knowing it had some value, I had it professionally graded about 10 years ago. At the time, it was worth $300. With the current trading card boom, it's now worth $1,100.

I have no interest in selling it, though.
Here's a photo of Dr. J swooping in for a layup at the RAC...