They are pretty advanced and pretty esoteric. They will be very difficult to get into without a solid graduate background in some of this stuff, or unless you're willing to roll up your sleeves and do some serious learning. The book "Applied Stochastic Analysis" by Weinan E, Tiejun Li, and Eric Vanden-Eijnden is probably a decent place to start. I took a look at this book a while ago, and it's probably decent enough to get a foothold on the literature in order to figure out if this stuff will be useful for you. These guys are all monsters in the field.