I got mine from India, a long time ago, so I don't remember address or source. It was a gift from a basenoter. I have two oils. One is average grade and is VERY sharp and anymalic in a sweaty way. The other is top grade and is balsamic, dark and faecal.
From what I read in other descriptions, there are ouds that have these same characteristics without being faecal. That would be nice from my point of view. I am sure that other more powerful basenoters will be able to tell you the best websites where to buy the stuff.