I need historical data for SSO, as much as I can get my hands on, for import to NinjaTrader. 1-minute and 15-sec (or shorter) bars, OHLC. I already have more than e-Signal could provide me with, i.e. I already have: - last 12-months of 1-min - last 5-months of 15-sec I am looking for a way to get historical data earlier than the above. Any suggestions? Thanks in advance.