Hello, I was wondering if anyone knows where I can find more information on crude oil calendar spreads. I want to know the seasonal historical spreads. I also want to know if there is any article on how calendar spreads can affect the price of crude. I want to understand why spread between April & May Crude oil has widened from $0.60 to $1.30 in less than a month. Is this typical or caused by market makers etc. Thank you.